try with lambda

templates/add_all_member_roles.json.j2

@@ -56,6 +56,15 @@
                 "queryExpression" : "[.role]"
             }
         },
+		{
+			"name": "LAMBDA_TASK",
+			"taskReferenceName": "to_role_array",
+			"type": "LAMBDA",
+			"inputParameters": {
+				"role": "${retrieve_member_role.output.body}",
+				"scriptExpression": "return Java.to([$.role], 'java.lang.Object[]')}"
+			}
+		},
 		{
 			"name" : "pyrest",
 			"type" : "SIMPLE",