diff --git a/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Data/Types/AssemblyData.cs b/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Data/Types/AssemblyData.cs
index 5da42f383..c9026464b 100644
--- a/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Data/Types/AssemblyData.cs
+++ b/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Data/Types/AssemblyData.cs
@@ -24,7 +24,7 @@ public class AssemblyData : ICloneable
         /// and then type name.
         /// </summary>
         [DataMember(EmitDefaultValue = false)]
-        public JsonCaseInsensitiveStringDictionary<JsonCaseInsensitiveStringDictionary<TypeData>> Types { get; set; }
+        public JsonDictionary<string, JsonDictionary<string, TypeData>> Types { get; set; }
 
         /// <summary>
         /// Create a deep clone of the assembly data object.
@@ -34,7 +34,7 @@ public object Clone()
             return new AssemblyData()
             {
                 AssemblyName = (AssemblyNameData)AssemblyName.Clone(),
-                Types = (JsonCaseInsensitiveStringDictionary<JsonCaseInsensitiveStringDictionary<TypeData>>)Types?.Clone()
+                Types = (JsonDictionary<string, JsonDictionary<string, TypeData>>)Types?.Clone()
             };
         }
     }
diff --git a/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Data/Types/AvailableTypeData.cs b/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Data/Types/AvailableTypeData.cs
index d721ce147..e876b1051 100644
--- a/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Data/Types/AvailableTypeData.cs
+++ b/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Data/Types/AvailableTypeData.cs
@@ -26,7 +26,7 @@ public class AvailableTypeData : ICloneable
         /// keyed by simple assembly name.
         /// </summary>
         [DataMember]
-        public JsonCaseInsensitiveStringDictionary<AssemblyData> Assemblies { get; set; }
+        public JsonDictionary<string, AssemblyData> Assemblies { get; set; }
 
         /// <summary>
         /// Create a deep clone of the available type data object.
@@ -36,7 +36,7 @@ public object Clone()
             return new AvailableTypeData()
             {
                 TypeAccelerators = (JsonCaseInsensitiveStringDictionary<TypeAcceleratorData>)TypeAccelerators.Clone(),
-                Assemblies = (JsonCaseInsensitiveStringDictionary<AssemblyData>)Assemblies.Clone()
+                Assemblies = (JsonDictionary<string, AssemblyData>)Assemblies.Clone()
             };
         }
     }
diff --git a/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Data/Types/MemberData.cs b/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Data/Types/MemberData.cs
index 5206cae54..7ba92fedc 100644
--- a/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Data/Types/MemberData.cs
+++ b/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Data/Types/MemberData.cs
@@ -26,13 +26,13 @@ public class MemberData : ICloneable
         /// Fields on the type, keyed by field name.
         /// </summary>
         [DataMember(EmitDefaultValue = false)]
-        public JsonCaseInsensitiveStringDictionary<FieldData> Fields { get; set; }
+        public JsonDictionary<string, FieldData> Fields { get; set; }
 
         /// <summary>
         /// Properties on this type, keyed by property name.
         /// </summary>
         [DataMember(EmitDefaultValue = false)]
-        public JsonCaseInsensitiveStringDictionary<PropertyData> Properties { get; set; }
+        public JsonDictionary<string, PropertyData> Properties { get; set; }
 
         /// <summary>
         /// Indexers on the type.
@@ -44,19 +44,19 @@ public class MemberData : ICloneable
         /// Methods on the type, keyed by method name.
         /// </summary>
         [DataMember(EmitDefaultValue = false)]
-        public JsonCaseInsensitiveStringDictionary<MethodData> Methods { get; set; }
+        public JsonDictionary<string, MethodData> Methods { get; set; }
 
         /// <summary>
         /// Events on the type, keyed by event name.
         /// </summary>
         [DataMember(EmitDefaultValue = false)]
-        public JsonCaseInsensitiveStringDictionary<EventData> Events { get; set; }
+        public JsonDictionary<string, EventData> Events { get; set; }
 
         /// <summary>
         /// Types nested within the type, keyed by type name.
         /// </summary>
         [DataMember(EmitDefaultValue = false)]
-        public JsonCaseInsensitiveStringDictionary<TypeData> NestedTypes { get; set; }
+        public JsonDictionary<string, TypeData> NestedTypes { get; set; }
 
         /// <summary>
         /// Create a deep clone of the member data object.
@@ -66,12 +66,12 @@ public object Clone()
             return new MemberData()
             {
                 Constructors = Constructors?.Select(c => (string[])c.Clone()).ToArray(),
-                Events = (JsonCaseInsensitiveStringDictionary<EventData>)Events?.Clone(),
-                Fields = (JsonCaseInsensitiveStringDictionary<FieldData>)Fields?.Clone(),
+                Events = (JsonDictionary<string, EventData>)Events?.Clone(),
+                Fields = (JsonDictionary<string, FieldData>)Fields?.Clone(),
                 Indexers = Indexers?.Select(i => (IndexerData)i.Clone()).ToArray(),
-                Methods = (JsonCaseInsensitiveStringDictionary<MethodData>)Methods?.Clone(),
-                NestedTypes = (JsonCaseInsensitiveStringDictionary<TypeData>)NestedTypes?.Clone(),
-                Properties = (JsonCaseInsensitiveStringDictionary<PropertyData>)Properties?.Clone(),
+                Methods = (JsonDictionary<string, MethodData>)Methods?.Clone(),
+                NestedTypes = (JsonDictionary<string, TypeData>)NestedTypes?.Clone(),
+                Properties = (JsonDictionary<string, PropertyData>)Properties?.Clone(),
             };
         }
     }
diff --git a/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Query/Types/AssemblyData.cs b/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Query/Types/AssemblyData.cs
index 74c6bc12d..2f996fd22 100644
--- a/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Query/Types/AssemblyData.cs
+++ b/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Query/Types/AssemblyData.cs
@@ -38,10 +38,10 @@ public AssemblyData(Data.Types.AssemblyData assemblyData)
         /// </summary>
         public IReadOnlyDictionary<string, IReadOnlyDictionary<string, TypeData>> Types => _types?.Value;
 
-        private static IReadOnlyDictionary<string, IReadOnlyDictionary<string, TypeData>> CreateTypeDictionary(IReadOnlyDictionary<string, JsonCaseInsensitiveStringDictionary<Data.Types.TypeData>> typeData)
+        private static IReadOnlyDictionary<string, IReadOnlyDictionary<string, TypeData>> CreateTypeDictionary(IReadOnlyDictionary<string, JsonDictionary<string, Data.Types.TypeData>> typeData)
         {
             var namespaceDict = new Dictionary<string, IReadOnlyDictionary<string, TypeData>>(typeData.Count, StringComparer.OrdinalIgnoreCase);
-            foreach (KeyValuePair<string, JsonCaseInsensitiveStringDictionary<Data.Types.TypeData>> nspace in typeData)
+            foreach (KeyValuePair<string, JsonDictionary<string, Data.Types.TypeData>> nspace in typeData)
             {
                 var typeDict = new Dictionary<string, TypeData>(nspace.Value.Count, StringComparer.OrdinalIgnoreCase);
                 foreach (KeyValuePair<string, Data.Types.TypeData> type in nspace.Value)
diff --git a/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Utility/ProfileCombination.cs b/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Utility/ProfileCombination.cs
index 314274b6d..dabdc869c 100644
--- a/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Utility/ProfileCombination.cs
+++ b/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Utility/ProfileCombination.cs
@@ -122,7 +122,7 @@ private static object Union(ParameterSetData thisParameterSet, ParameterSetData
 
         private static object Union(AvailableTypeData thisTypes, AvailableTypeData thatTypes)
         {
-            thisTypes.Assemblies = StringDictionaryUnion(thisTypes.Assemblies, thatTypes.Assemblies, Union);
+            thisTypes.Assemblies = DictionaryUnion(thisTypes.Assemblies, thatTypes.Assemblies, Union);
             thisTypes.TypeAccelerators = StringDictionaryUnion(thisTypes.TypeAccelerators, thatTypes.TypeAccelerators);
 
             return thisTypes;
@@ -136,10 +136,10 @@ private static object Union(AssemblyData thisAssembly, AssemblyData thatAssembly
             {
                 if (thisAssembly.Types == null)
                 {
-                    thisAssembly.Types = new JsonCaseInsensitiveStringDictionary<JsonCaseInsensitiveStringDictionary<TypeData>>();
+                    thisAssembly.Types = new JsonDictionary<string, JsonDictionary<string, TypeData>>();
                 }
 
-                foreach (KeyValuePair<string, JsonCaseInsensitiveStringDictionary<TypeData>> nspace in thatAssembly.Types)
+                foreach (KeyValuePair<string, JsonDictionary<string, TypeData>> nspace in thatAssembly.Types)
                 {
                     if (!thisAssembly.Types.ContainsKey(nspace.Key))
                     {
@@ -147,7 +147,7 @@ private static object Union(AssemblyData thisAssembly, AssemblyData thatAssembly
                         continue;
                     }
 
-                    thisAssembly.Types[nspace.Key] = StringDictionaryUnion(thisAssembly.Types[nspace.Key], nspace.Value, Union);
+                    thisAssembly.Types[nspace.Key] = DictionaryUnion(thisAssembly.Types[nspace.Key], nspace.Value, Union);
                 }
             }
 
@@ -192,11 +192,11 @@ private static object Union(MemberData thisMembers, MemberData thatMembers)
 
             thisMembers.Constructors = ParameterUnion(thisMembers.Constructors, thatMembers.Constructors);
 
-            thisMembers.Events = StringDictionaryUnion(thisMembers.Events, thatMembers.Events);
-            thisMembers.Fields = StringDictionaryUnion(thisMembers.Fields, thatMembers.Fields);
-            thisMembers.Methods = StringDictionaryUnion(thisMembers.Methods, thatMembers.Methods, Union);
-            thisMembers.NestedTypes = StringDictionaryUnion(thisMembers.NestedTypes, thatMembers.NestedTypes, Union);
-            thisMembers.Properties = StringDictionaryUnion(thisMembers.Properties, thatMembers.Properties, Union);
+            thisMembers.Events = DictionaryUnion(thisMembers.Events, thatMembers.Events);
+            thisMembers.Fields = DictionaryUnion(thisMembers.Fields, thatMembers.Fields);
+            thisMembers.Methods = DictionaryUnion(thisMembers.Methods, thatMembers.Methods, Union);
+            thisMembers.NestedTypes = DictionaryUnion(thisMembers.NestedTypes, thatMembers.NestedTypes, Union);
+            thisMembers.Properties = DictionaryUnion(thisMembers.Properties, thatMembers.Properties, Union);
 
             return thisMembers;
         }
diff --git a/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Utility/TypeDataConversion.cs b/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Utility/TypeDataConversion.cs
index 0faa00854..c9f93f762 100644
--- a/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Utility/TypeDataConversion.cs
+++ b/PSCompatibilityAnalyzer/Microsoft.PowerShell.CrossCompatibility/Utility/TypeDataConversion.cs
@@ -50,7 +50,7 @@ public static AvailableTypeData AssembleAvailableTypes(
                 typeAcceleratorDict.Add(typeAccelerator.Key, ta);
             }
 
-            var asms = new JsonCaseInsensitiveStringDictionary<AssemblyData>();
+            var asms = new JsonDictionary<string, AssemblyData>();
             foreach (Assembly asm in assemblies)
             {
                 // Don't want to include this module or assembly in the output
@@ -61,8 +61,17 @@ public static AvailableTypeData AssembleAvailableTypes(
 
                 try
                 {
+                    // First check whether an assembly with this name already exists
+                    // Only replace it if the current one is newer
+                    AssemblyName asmName = asm.GetName();
+                    if (asms.TryGetValue(asmName.Name, out AssemblyData currentAssemblyData)
+                        && asmName.Version < currentAssemblyData.AssemblyName.Version)
+                    {
+                        continue;
+                    }
+
                     KeyValuePair<string, AssemblyData> asmData = AssembleAssembly(asm);
-                    asms.Add(asmData.Key, asmData.Value);
+                    asms[asmData.Key] = asmData.Value;
                 }
                 catch (ReflectionTypeLoadException e)
                 {
@@ -96,10 +105,10 @@ public static KeyValuePair<string, AssemblyData> AssembleAssembly(Assembly asm)
             };
 
             Type[] types = asm.GetTypes();
-            JsonCaseInsensitiveStringDictionary<JsonCaseInsensitiveStringDictionary<TypeData>> namespacedTypes = null;
+            JsonDictionary<string, JsonDictionary<string, TypeData>> namespacedTypes = null;
             if (types.Any())
             {
-                namespacedTypes = new JsonCaseInsensitiveStringDictionary<JsonCaseInsensitiveStringDictionary<TypeData>>();
+                namespacedTypes = new JsonDictionary<string, JsonDictionary<string, TypeData>>();
                 foreach (Type type in asm.GetTypes())
                 {
                     if (!type.IsPublic)
@@ -110,14 +119,14 @@ public static KeyValuePair<string, AssemblyData> AssembleAssembly(Assembly asm)
                     // Some types don't have a namespace, but we still want to file them
                     string typeNamespace = type.Namespace ?? "";
 
-                    if (!namespacedTypes.ContainsKey(typeNamespace))
+                    if (!namespacedTypes.TryGetValue(typeNamespace, out JsonDictionary<string, TypeData> typeDictionary))
                     {
-                        namespacedTypes.Add(typeNamespace, new JsonCaseInsensitiveStringDictionary<TypeData>());
+                        typeDictionary = new JsonDictionary<string, TypeData>();
                     }
 
                     TypeData typeData = AssembleType(type);
 
-                    namespacedTypes[typeNamespace][type.Name] = typeData;
+                    typeDictionary[type.Name] = typeData;
                 }
             }
 
@@ -271,12 +280,12 @@ private static MemberData AssembleMembers(Type type, BindingFlags memberBinding)
             return new MemberData()
             {
                 Constructors = constructors.Any() ? constructors.Select(c => AssembleConstructor(c)).ToArray() : null,
-                Events = events.Any() ? new JsonCaseInsensitiveStringDictionary<EventData>(events.ToDictionary(e => e.Name, e => AssembleEvent(e), StringComparer.OrdinalIgnoreCase)) : null,
-                Fields = fields.Any() ? new JsonCaseInsensitiveStringDictionary<FieldData>(fields.ToDictionary(f => f.Name, f => AssembleField(f), StringComparer.OrdinalIgnoreCase)) : null,
+                Events = events.Any() ? new JsonDictionary<string, EventData>(events.ToDictionary(e => e.Name, e => AssembleEvent(e))) : null,
+                Fields = fields.Any() ? new JsonDictionary<string, FieldData>(fields.ToDictionary(f => f.Name, f => AssembleField(f))) : null,
                 Indexers = indexers.Any() ? indexers.Select(i => AssembleIndexer(i)).ToArray() : null,
-                Methods = methods.Any() ? new JsonCaseInsensitiveStringDictionary<MethodData>(methods.ToDictionary(m => m.Key, m => AssembleMethod(m.Value), StringComparer.OrdinalIgnoreCase)) : null,
-                NestedTypes = nestedTypes.Any() ? new JsonCaseInsensitiveStringDictionary<TypeData>(nestedTypes.ToDictionary(t => t.Name, t => AssembleType(t), StringComparer.OrdinalIgnoreCase)) : null,
-                Properties = properties.Any() ? new JsonCaseInsensitiveStringDictionary<PropertyData>(properties.ToDictionary(p => p.Name, p => AssembleProperty(p), StringComparer.OrdinalIgnoreCase)) : null
+                Methods = methods.Any() ? new JsonDictionary<string, MethodData>(methods.ToDictionary(m => m.Key, m => AssembleMethod(m.Value))) : null,
+                NestedTypes = nestedTypes.Any() ? new JsonDictionary<string, TypeData>(nestedTypes.ToDictionary(t => t.Name, t => AssembleType(t))) : null,
+                Properties = properties.Any() ? new JsonDictionary<string, PropertyData>(properties.ToDictionary(p => p.Name, p => AssembleProperty(p))) : null
             };
         }
 
diff --git a/PSCompatibilityAnalyzer/Tests/QueryApi.Tests.ps1 b/PSCompatibilityAnalyzer/Tests/QueryApi.Tests.ps1
new file mode 100644
index 000000000..a374f40b7
--- /dev/null
+++ b/PSCompatibilityAnalyzer/Tests/QueryApi.Tests.ps1
@@ -0,0 +1,36 @@
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License.
+
+Describe ".NET type with members with names differing only by name" {
+    BeforeAll {
+        Add-Type -TypeDefinition @'
+namespace PSScriptAnalyzerTests
+{
+    public class QueryApiTestObject
+    {
+        public string JobId { get; set; }
+
+        public object JOBID { get; set; }
+    }
+}
+'@
+    }
+
+    It "Does not crash the query API" {
+        $typeData = [Microsoft.PowerShell.CrossCompatibility.Utility.TypeDataConversion]::AssembleType([PSScriptAnalyzerTests.QueryApiTestObject])
+
+        $typeQueryObject = New-Object 'Microsoft.PowerShell.CrossCompatibility.Query.TypeData' ('QueryApiTestObject', $typeData)
+
+        $typeData.Instance.Properties.Count | Should -Be 2
+
+        $typeData.Instance.Properties.ContainsKey('JobId') | Should -BeTrue
+        $typeData.Instance.Properties.ContainsKey('JOBID') | Should -BeTrue
+        $typeData.Instance.Properties.ContainsKey('jobid') | Should -Not -BeTrue
+
+        $typeQueryObject.Instance.Properties.Count | Should -Be 1
+
+        $typeQueryObject.Instance.Properties.ContainsKey('JobId') | Should -BeTrue
+        $typeQueryObject.Instance.Properties.ContainsKey('JobID') | Should -BeTrue
+        $typeQueryObject.Instance.Properties.ContainsKey('jobid') | Should -BeTrue
+    }
+}
\ No newline at end of file