diff --git a/src/Bicep.Core/TypeSystem/Providers/Az/AzResourceTypeFactory.cs b/src/Bicep.Core/TypeSystem/Providers/Az/AzResourceTypeFactory.cs
index 70f885ac129..305ae209634 100644
--- a/src/Bicep.Core/TypeSystem/Providers/Az/AzResourceTypeFactory.cs
+++ b/src/Bicep.Core/TypeSystem/Providers/Az/AzResourceTypeFactory.cs
@@ -57,6 +57,7 @@ public IEnumerable<FunctionOverload> GetResourceFunctionOverloads(Azure.Bicep.Ty
         }
 
         private TypeSymbol GetTypeSymbol(Azure.Bicep.Types.Concrete.TypeBase serializedType, bool isResourceBodyType, bool isResourceBodyTopLevelPropertyType)
+            // The cache key should always include *all* arguments passed to this function
             => typeCache.GetOrAdd((serializedType, isResourceBodyType, isResourceBodyTopLevelPropertyType),
                 t => ToTypeSymbol(t.definedType, t.isResourceBodyType, t.isResourceBodyTopLevelPropertyType));