diff --git a/templates/group_created.json.j2 b/templates/group_created.json.j2
index 2ba1747..204b44b 100644
--- a/templates/group_created.json.j2
+++ b/templates/group_created.json.j2
@@ -441,7 +441,7 @@
       "inputParameters": {
         "memberpolicy" : "${create_role_policy_member.output.body.id}",
         "otherpolicies" : "${join_parallel_policy_addition.output[*].body.id}",
-        "scriptExpression": "return $.otherpolicies.concat($.memberpolicy)"
+        "scriptExpression": "return Java.to(Java.from($.otherpolicies).concat($.memberpolicy), 'java.lang.String[]')"
       }
     },
 		{