diff --git a/implementation/src/main/java/io/smallrye/config/ConfigMappingProvider.java b/implementation/src/main/java/io/smallrye/config/ConfigMappingProvider.java
index 9bb9aad98..905a8b18a 100644
--- a/implementation/src/main/java/io/smallrye/config/ConfigMappingProvider.java
+++ b/implementation/src/main/java/io/smallrye/config/ConfigMappingProvider.java
@@ -439,11 +439,22 @@ private void processLazyMap(
 
             addAction(currentPath, property, (mc, ni) -> {
                 StringBuilder sb = mc.getStringBuilder();
-                sb.setLength(0);
-                sb.append(ni.getAllPreviousSegments());
+                // We may need to reset the StringBuilder because the delegate may not be a Map
+                boolean restore = false;
+                if (ni.getPosition() != -1) {
+                    restore = true;
+                    ni.previous();
+                    sb.setLength(0);
+                    sb.append(ni.getAllPreviousSegments());
+                }
+                Map<?, ?> map = getEnclosingMap.apply(mc, ni);
+                if (restore) {
+                    ni.next();
+                    sb.setLength(0);
+                    sb.append(ni.getAllPreviousSegments());
+                }
                 String configKey = sb.toString();
                 String rawMapKey = ni.getPreviousSegment();
-                Map<?, ?> map = getEnclosingMap.apply(mc, ni);
                 Converter<?> keyConv;
                 SmallRyeConfig config = mc.getConfig();
                 if (keyConvertWith != null) {
@@ -463,7 +474,9 @@ private void processLazyMap(
         } else if (valueProperty.isMap()) {
             currentPath.addLast("*");
             processLazyMap(currentPath, matchActions, defaultValues, valueProperty.asMap(), (mc, ni) -> {
+                ni.previous();
                 Map<?, ?> enclosingMap = getEnclosingMap.apply(mc, ni);
+                ni.next();
                 String rawMapKey = ni.getPreviousSegment();
                 Converter<?> keyConv;
                 SmallRyeConfig config = mc.getConfig();
@@ -626,7 +639,9 @@ static class GetOrCreateEnclosingGroupInMap implements BiFunction<ConfigMappingC
 
         @SuppressWarnings({ "unchecked", "rawtypes" })
         public ConfigMappingObject apply(final ConfigMappingContext context, final NameIterator ni) {
+            ni.previous();
             Map<?, ?> ourEnclosing = getEnclosingMap.apply(context, ni);
+            ni.next();
             String mapKey = mapKey(ni);
             Converter<?> keyConverter = context.getKeyConverter(enclosingGroup.getInterfaceType(),
                     enclosingMap.getMethod().getName(), enclosingMap.getLevels() - 1);
@@ -693,23 +708,7 @@ static class GetOrCreateEnclosingMapInGroup implements BiFunction<ConfigMappingC
             boolean consumeName = !enclosedGroup.isParentPropertyName();
             if (consumeName)
                 ni.previous();
-
-            // We may need to reset the StringBuilder because the delegate may not be a Map
-            boolean restore = false;
-            StringBuilder sb = context.getStringBuilder();
-            if (ni.getPosition() != -1) {
-                restore = true;
-                ni.previous();
-                sb.setLength(0);
-                sb.append(ni.getAllPreviousSegments());
-            }
             ConfigMappingObject ourEnclosing = delegate.apply(context, ni);
-            // Restore
-            if (restore) {
-                ni.next();
-                sb.setLength(0);
-                sb.append(ni.getAllPreviousSegments());
-            }
             if (consumeName)
                 ni.next();
             Class<?> enclosingType = enclosingGroup.getInterfaceType();
diff --git a/implementation/src/test/java/io/smallrye/config/ConfigMappingInterfaceTest.java b/implementation/src/test/java/io/smallrye/config/ConfigMappingInterfaceTest.java
index 26b2e9c38..cdab95343 100644
--- a/implementation/src/test/java/io/smallrye/config/ConfigMappingInterfaceTest.java
+++ b/implementation/src/test/java/io/smallrye/config/ConfigMappingInterfaceTest.java
@@ -1488,4 +1488,47 @@ void nestedOptionalsGroupMap() {
         assertEquals("value", mapping.first().get().second().get().third().get().properties().get("key"));
         assertEquals("value", mapping.first().get().second().get().third().get().value());
     }
+
+    @ConfigMapping(prefix = "optional-map")
+    public interface NestedOptionalMapGroup {
+        Optional<Boolean> enable();
+
+        Map<String, Map<String, MessageUtilConfiguration>> map();
+
+        interface MessageUtilConfiguration {
+            Optional<Boolean> enable();
+        }
+    }
+
+    @Test
+    void nestedOptionalAndMaps() {
+        SmallRyeConfig config = new SmallRyeConfigBuilder()
+                .withMapping(NestedOptionalMapGroup.class)
+                .withSources(config("optional-map.enable", "true"))
+                .withSources(config("optional-map.map.filter.default.enable", "false",
+                        "optional-map.map.filter.get-jokes-uni.enable", "true"))
+                .withSources(config("optional-map.map.client.reaction-api.enable", "true",
+                        "optional-map.map.client.setup-api.enable", "true"))
+                .build();
+
+        NestedOptionalMapGroup mapping = config.getConfigMapping(NestedOptionalMapGroup.class);
+        assertTrue(mapping.enable().isPresent());
+        assertTrue(mapping.enable().get());
+
+        assertEquals(2, mapping.map().size());
+        assertTrue(mapping.map().containsKey("filter"));
+        assertTrue(mapping.map().get("filter").containsKey("default"));
+        assertTrue(mapping.map().get("filter").containsKey("get-jokes-uni"));
+        assertTrue(mapping.map().containsKey("client"));
+        assertTrue(mapping.map().get("client").containsKey("reaction-api"));
+        assertTrue(mapping.map().get("client").containsKey("setup-api"));
+        assertTrue(mapping.map().get("filter").get("default").enable().isPresent());
+        assertFalse(mapping.map().get("filter").get("default").enable().get());
+        assertTrue(mapping.map().get("filter").get("get-jokes-uni").enable().isPresent());
+        assertTrue(mapping.map().get("filter").get("get-jokes-uni").enable().get());
+        assertTrue(mapping.map().get("client").get("reaction-api").enable().isPresent());
+        assertTrue(mapping.map().get("client").get("reaction-api").enable().get());
+        assertTrue(mapping.map().get("client").get("setup-api").enable().isPresent());
+        assertTrue(mapping.map().get("client").get("setup-api").enable().get());
+    }
 }