diff --git a/src/Utils/isAssignableTo.ts b/src/Utils/isAssignableTo.ts
index 051297067..ae486dc32 100644
--- a/src/Utils/isAssignableTo.ts
+++ b/src/Utils/isAssignableTo.ts
@@ -196,12 +196,7 @@ export function isAssignableTo(
         const targetMembers = getObjectProperties(target);
         if (targetMembers.length === 0) {
             // When target object is empty then anything except null and undefined can be assigned to it
-            return !isAssignableTo(
-                new UnionType([new UndefinedType(), new NullType()]).normalize(),
-                source,
-                inferMap,
-                insideTypes
-            );
+            return !isAssignableTo(new UnionType([new UndefinedType(), new NullType()]), source, inferMap, insideTypes);
         } else if (source instanceof ObjectType) {
             const sourceMembers = getObjectProperties(source);