diff --git a/sources/yaml/src/main/java/io/smallrye/config/source/yaml/YamlConfigSource.java b/sources/yaml/src/main/java/io/smallrye/config/source/yaml/YamlConfigSource.java
index 19400f14b..4f017898f 100644
--- a/sources/yaml/src/main/java/io/smallrye/config/source/yaml/YamlConfigSource.java
+++ b/sources/yaml/src/main/java/io/smallrye/config/source/yaml/YamlConfigSource.java
@@ -8,10 +8,8 @@
 import java.net.URL;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 import java.util.TreeMap;
 import java.util.function.Function;
 import java.util.stream.Collectors;
@@ -47,11 +45,8 @@ public class YamlConfigSource extends MapBackedConfigSource {
         DUMPER = new Yaml(dumperOptions);
     }
 
-    private final Set<String> propertyNames;
-
     public YamlConfigSource(String name, Map<String, String> source, int ordinal) {
         super(name, source, ordinal, false);
-        this.propertyNames = filterPropertyNames(source);
     }
 
     public YamlConfigSource(URL url) throws IOException {
@@ -77,11 +72,6 @@ public YamlConfigSource(String name, String source, int ordinal) {
         this(name, stringToMap(source), ordinal);
     }
 
-    @Override
-    public Set<String> getPropertyNames() {
-        return propertyNames;
-    }
-
     @SuppressWarnings("unchecked")
     private static Map<String, String> streamToMap(InputStream inputStream) throws IOException {
         Assert.checkNotNullParam("inputStream", inputStream);
@@ -181,12 +171,6 @@ private static void flattenList(String key, List<Object> source, Map<String, Str
                 escapeCommas(sb, value, 1);
                 return sb.toString();
             }).collect(Collectors.joining(",")));
-        } else {
-            // Mark keys for later removal
-            key = YamlConfigSource.class.getName() + ".filter." + key;
-            // This dumps the entire YAML in a parent property. It was added to support complex mappings, but it is not
-            // needed anymore with the indexed property support. We keep it for compatibility reasons.
-            target.put(key, DUMPER.dump(singletonMap(key.substring(key.lastIndexOf(".") + 1), source)));
         }
     }
 
@@ -203,19 +187,6 @@ private static void escapeCommas(StringBuilder b, String src, int escapeLevel) {
         }
     }
 
-    private static Set<String> filterPropertyNames(Map<String, String> source) {
-        final Set<String> filteredKeys = new HashSet<>();
-        for (final String key : new HashSet<>(source.keySet())) {
-            if (key.startsWith(YamlConfigSource.class.getName() + ".filter.")) {
-                String originalKey = key.substring(55);
-                source.put(originalKey, source.remove(key));
-            } else {
-                filteredKeys.add(key);
-            }
-        }
-        return filteredKeys;
-    }
-
     /**
      * Override some yaml constructors, so that the value written in the flatten result is more alike with the
      * source. For instance, timestamps may be written in a completely different format which prevents converters to
diff --git a/sources/yaml/src/test/java/io/smallrye/config/source/yaml/YamlConfigSourceTest.java b/sources/yaml/src/test/java/io/smallrye/config/source/yaml/YamlConfigSourceTest.java
index 7eccf8fe5..9c1a73d66 100644
--- a/sources/yaml/src/test/java/io/smallrye/config/source/yaml/YamlConfigSourceTest.java
+++ b/sources/yaml/src/test/java/io/smallrye/config/source/yaml/YamlConfigSourceTest.java
@@ -26,34 +26,6 @@
 import io.smallrye.config.SmallRyeConfigBuilder;
 
 class YamlConfigSourceTest {
-    @Test
-    void flatten() {
-        String yaml = "admin:\n" +
-                "  users:\n" +
-                "    -\n" +
-                "      email: \"joe@gmail.com\"\n" +
-                "      username: \"joe\"\n" +
-                "      password: \"123456\"\n" +
-                "      roles:\n" +
-                "        - \"Moderator\"\n" +
-                "        - \"Admin\"\n" +
-                "    -\n" +
-                "      email: \"jack@gmail.com\"\n" +
-                "      username: \"jack\"\n" +
-                "      password: \"654321\"\n" +
-                "      roles:\n" +
-                "        - \"Moderator\"\n";
-
-        YamlConfigSource source = new YamlConfigSource("yaml", yaml);
-        String value = source.getValue("admin.users");
-        Users users = new UserConverter().convert(value);
-        assertEquals(2, users.getUsers().size());
-        assertEquals(users.users.get(0).getEmail(), "joe@gmail.com");
-        assertEquals(users.users.get(0).getRoles(), Stream.of("Moderator", "Admin").collect(toList()));
-
-        assertEquals("joe@gmail.com", source.getValue("admin.users[0].email"));
-    }
-
     @Test
     void profiles() {
         String yaml = "---\n" +
@@ -149,37 +121,6 @@ void indentSpaces() {
         assertEquals("smallrye", config.getRawValue("greeting.name"));
     }
 
-    @Test
-    void config() {
-        String yaml = "admin:\n" +
-                "  users:\n" +
-                "    -\n" +
-                "      email: \"joe@gmail.com\"\n" +
-                "      username: \"joe\"\n" +
-                "      password: \"123456\"\n" +
-                "      roles:\n" +
-                "        - \"Moderator\"\n" +
-                "        - \"Admin\"\n" +
-                "    -\n" +
-                "      email: \"jack@gmail.com\"\n" +
-                "      username: \"jack\"\n" +
-                "      password: \"654321\"\n" +
-                "      roles:\n" +
-                "        - \"Moderator\"\n";
-
-        SmallRyeConfig config = new SmallRyeConfigBuilder()
-                .withSources(new YamlConfigSource("yaml", yaml))
-                .withConverter(Users.class, 100, new UserConverter())
-                .build();
-
-        Users users = config.getValue("admin.users", Users.class);
-        assertEquals(2, users.getUsers().size());
-        assertEquals(users.users.get(0).getEmail(), "joe@gmail.com");
-        assertEquals(users.users.get(0).getRoles(), Stream.of("Moderator", "Admin").collect(toList()));
-
-        assertEquals("joe@gmail.com", config.getRawValue("admin.users[0].email"));
-    }
-
     @Test
     void propertyNames() {
         String yaml = "quarkus:\n" +