diff --git a/packages/quicktype-core/src/UnifyClasses.ts b/packages/quicktype-core/src/UnifyClasses.ts
index 5c1e0094eb..63deb15a62 100644
--- a/packages/quicktype-core/src/UnifyClasses.ts
+++ b/packages/quicktype-core/src/UnifyClasses.ts
@@ -191,6 +191,7 @@ export class UnifyUnionBuilder extends UnionBuilder<
             return this.typeBuilder.getMapType(
                 typeAttributes,
                 this._unifyTypes(Array.from(propertyTypes)),
+                forwardingRef,
             );
         } else {
             const [properties, additionalProperties, lostTypeAttributes] =
diff --git a/test/inputs/json/priority/bug2037.json b/test/inputs/json/priority/bug2037.json
new file mode 100644
index 0000000000..3c02da6267
--- /dev/null
+++ b/test/inputs/json/priority/bug2037.json
@@ -0,0 +1 @@
+{"mission_specs": {"1": {"objectives": {"2": {"rewards": {"3": {}, "5": {}}}}}, "4": {"objectives": {"6": {"rewards": {}}}}}}
diff --git a/test/languages.ts b/test/languages.ts
index a31f78b6f5..14148e136a 100644
--- a/test/languages.ts
+++ b/test/languages.ts
@@ -1168,6 +1168,8 @@ export const KotlinLanguage: Language = {
         "nst-test-suite.json",
         // Klaxon does not support top-level primitives
         "no-classes.json",
+        // Klaxon cannot deserialize empty object map values as JsonObject: #2881
+        "bug2037.json",
         // These should be enabled
         "nbl-stats.json",
         // TODO Investigate these