Have you checked the arguments of all the workflow files that are executed to get to this workflow file here? I believe at some point the flow is broken because it looks like the in_Config_test is not really getting the dictionary data from the workflow its being called.
You can easily keep track of this by using the Debug mode. Have a breakpoint there in the invoke workflow activity and run the program. Once it reach the activity, check in your Locale panel whether the config variables/ arguments have data in it. This will help you figure out from where it’s going missing…
Hope it helps