diff --git a/src/Resources/ResourceManager/Formatters/WhatIfOperationResultFormatter.cs b/src/Resources/ResourceManager/Formatters/WhatIfOperationResultFormatter.cs
index 501973aecdf1..5037740378f7 100644
--- a/src/Resources/ResourceManager/Formatters/WhatIfOperationResultFormatter.cs
+++ b/src/Resources/ResourceManager/Formatters/WhatIfOperationResultFormatter.cs
@@ -330,7 +330,7 @@ private void FormatPropertyChange(PSWhatIfPropertyChange propertyChange, int max
 
                 case PropertyChangeType.Array:
                     this.FormatPropertyChangePath(propertyChangeType, path, null, children, maxPathLength, indentLevel);
-                    this.FormatPropertyArrayChange(propertyChange.Children, indentLevel + 1);
+                    this.FormatPropertyArrayChange(propertyChange, propertyChange.Children, indentLevel + 1);
                     break;
 
                 case PropertyChangeType.NoEffect:
@@ -351,6 +351,11 @@ private void FormatPropertyChangePath(
             int maxPathLength,
             int indentLevel)
         {
+            if (string.IsNullOrEmpty(path))
+            {
+                return;
+            }
+
             int paddingWidth = maxPathLength - path.Length + 1;
             bool hasChildren = children != null && children.Count > 0;
 
@@ -449,8 +454,17 @@ private void FormatPropertyModify(PSWhatIfPropertyChange propertyChange, int ind
             }
         }
 
-        private void FormatPropertyArrayChange(IList<PSWhatIfPropertyChange> propertyChanges, int indentLevel)
+        private void FormatPropertyArrayChange(PSWhatIfPropertyChange parentPropertyChange, IList<PSWhatIfPropertyChange> propertyChanges, int indentLevel)
         {
+            if (string.IsNullOrEmpty(parentPropertyChange.Path))
+            {
+                // The parent change doesn't have a path, which means the current
+                // array change is a nested change. We need to decrease indent_level
+                // and print indentation before printing "[".
+                indentLevel--;
+                FormatIndent(indentLevel);
+            }
+
             if (propertyChanges.Count == 0)
             {
                 this.Builder.AppendLine("[]");
diff --git a/src/Resources/Resources.Test/Formatters/WhatIfOperationResultFormatterTests.cs b/src/Resources/Resources.Test/Formatters/WhatIfOperationResultFormatterTests.cs
index 2576fb29484c..de9ebca25b34 100644
--- a/src/Resources/Resources.Test/Formatters/WhatIfOperationResultFormatterTests.cs
+++ b/src/Resources/Resources.Test/Formatters/WhatIfOperationResultFormatterTests.cs
@@ -19,6 +19,7 @@ namespace Microsoft.Azure.Commands.Resources.Test.Formatters
     using ResourceManager.Cmdlets.SdkModels.Deployments;
     using System;
     using System.Collections.Generic;
+    using System.IO;
     using WindowsAzure.Commands.ScenarioTest;
     using Xunit;
 
@@ -441,6 +442,104 @@ public void Format_ChangeTypeModify_FormatsPropertyChanges()
             // Assert.
             Assert.Contains(expected, result);
         }
+
+        [Fact]
+        [Trait(Category.AcceptanceType, Category.CheckIn)]
+        public void Format_nested_array_changes_does_not_throw()
+        {
+            // Arrange.
+            var whatIfChanges = new List<WhatIfChange>
+            {
+                new WhatIfChange
+                {
+                    ResourceId = "/subscriptions/00000000-0000-0000-0000-000000000004/resourceGroups/rg4/providers/Microsoft.DocumentDB/databaseAccounts/myaccount/sqlDatabases/accesscontrol/containers/workflows",
+                    ChangeType = ChangeType.Modify,
+                    Delta = new List<WhatIfPropertyChange>
+                    {
+                        new WhatIfPropertyChange
+                        {
+                            Path = "properties.resource.indexingPolicy.compositeIndexes",
+                            PropertyChangeType = PropertyChangeType.Array,
+                            Children = new List<WhatIfPropertyChange>
+                            {
+                                new WhatIfPropertyChange
+                                {
+                                    Path = "0",
+                                    PropertyChangeType = PropertyChangeType.Modify,
+                                    Children = new List<WhatIfPropertyChange>
+                                    {
+                                        new WhatIfPropertyChange
+                                        {
+                                            Path = null,
+                                            PropertyChangeType = PropertyChangeType.Array,
+                                            Children = new List<WhatIfPropertyChange>
+                                            {
+                                                new WhatIfPropertyChange
+                                                {
+                                                    Path = "0",
+                                                    PropertyChangeType = PropertyChangeType.Modify,
+                                                    Children = new List<WhatIfPropertyChange>
+                                                    {
+                                                        new WhatIfPropertyChange
+                                                        {
+                                                            Path = "order",
+                                                            PropertyChangeType = PropertyChangeType.Delete,
+                                                            Before = "ascending",
+                                                        }
+                                                    }
+                                                },
+                                                new WhatIfPropertyChange
+                                                {
+                                                    Path = "1",
+                                                    PropertyChangeType = PropertyChangeType.Modify,
+                                                    Children = new List<WhatIfPropertyChange>
+                                                    {
+                                                        new WhatIfPropertyChange
+                                                        {
+                                                            Path = "order",
+                                                            PropertyChangeType = PropertyChangeType.Delete,
+                                                            Before = "ascending",
+                                                        }
+                                                    }
+                                                }
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        },
+                    }
+                }
+            };
+
+            string expected = $@"
+Scope: /subscriptions/00000000-0000-0000-0000-000000000004/resourceGroups/rg4
+{Color.Purple}
+  ~ Microsoft.DocumentDB/databaseAccounts/myaccount/sqlDatabases/accesscontrol/containers/workflows{Color.Reset}
+    {Color.Purple}~{Color.Reset} properties.resource.indexingPolicy.compositeIndexes{Color.Reset}:{Color.Reset} [
+      {Color.Purple}~{Color.Reset} 0{Color.Reset}:{Color.Reset}
+
+        [
+        {Color.Purple}~{Color.Reset} 0{Color.Reset}:{Color.Reset}
+
+          {Color.Orange}-{Color.Reset} order{Color.Reset}:{Color.Reset} {Color.Orange}""ascending""{Color.Reset}
+
+        {Color.Purple}~{Color.Reset} 1{Color.Reset}:{Color.Reset}
+
+          {Color.Orange}-{Color.Reset} order{Color.Reset}:{Color.Reset} {Color.Orange}""ascending""{Color.Reset}
+
+        ]
+
+      ]
+".Replace("\r\n", Environment.NewLine);
+
+            // Act.
+            string result = WhatIfOperationResultFormatter.Format(
+                new PSWhatIfOperationResult(new WhatIfOperationResult(changes: whatIfChanges)));
+
+            // Assert.
+            Assert.Contains(expected, result);
+        }
     }
 }
 
diff --git a/src/Resources/Resources/ChangeLog.md b/src/Resources/Resources/ChangeLog.md
index 99374ea919b1..da394d9a2902 100644
--- a/src/Resources/Resources/ChangeLog.md
+++ b/src/Resources/Resources/ChangeLog.md
@@ -19,6 +19,7 @@
 -->
 
 ## Upcoming Release
+* Fixed an issue where running deployment cmdlets with `-WhatIf` throws exception when formatting results with nested array changes
 
 ## Version 6.5.1
 * Fixed issue introduced in previous fix for `Set-AzPolicySetDefinition` InternalServerError when the initiative is too large [#20238], which will remove space in value.