diff --git a/conformance/src/test/java/dev/cel/conformance/BUILD.bazel b/conformance/src/test/java/dev/cel/conformance/BUILD.bazel
index 375cd8bfa..c8cc06cb0 100644
--- a/conformance/src/test/java/dev/cel/conformance/BUILD.bazel
+++ b/conformance/src/test/java/dev/cel/conformance/BUILD.bazel
@@ -175,7 +175,6 @@ _TESTS_TO_SKIP_PLANNER = [
     "timestamps/timestamp_range/sub_time_duration_under",
 
     # Skip until fixed.
-    "fields/qualified_identifier_resolution/map_value_repeat_key_heterogeneous",
     "optionals/optionals/map_null_entry_no_such_key",
     "optionals/optionals/map_present_key_invalid_field",
     "parse/receiver_function_names",
diff --git a/runtime/src/main/java/dev/cel/runtime/planner/EvalCreateMap.java b/runtime/src/main/java/dev/cel/runtime/planner/EvalCreateMap.java
index c09c19987..f6f73e842 100644
--- a/runtime/src/main/java/dev/cel/runtime/planner/EvalCreateMap.java
+++ b/runtime/src/main/java/dev/cel/runtime/planner/EvalCreateMap.java
@@ -59,13 +59,26 @@ public Object eval(GlobalResolver resolver, ExecutionFrame frame) throws CelEval
             keyInterpretable.exprId());
       }
 
-      Object val = values[i].eval(resolver, frame);
+      boolean isDuplicate = !keysSeen.add(key);
+      if (!isDuplicate) {
+        if (key instanceof Long) {
+          long longVal = (Long) key;
+          if (longVal >= 0) {
+            isDuplicate = keysSeen.contains(UnsignedLong.valueOf(longVal));
+          }
+        } else if (key instanceof UnsignedLong) {
+          UnsignedLong ulongVal = (UnsignedLong) key;
+          isDuplicate = keysSeen.contains(ulongVal.longValue());
+        }
+      }
 
-      if (!keysSeen.add(key)) {
+      if (isDuplicate) {
         throw new LocalizedEvaluationException(
             CelDuplicateKeyException.of(key), keyInterpretable.exprId());
       }
 
+      Object val = values[i].eval(resolver, frame);
+
       if (isOptional[i]) {
         if (!(val instanceof Optional)) {
           throw new IllegalArgumentException(