I'm glad you were able to find the root issue.
As for your follow up question, if something is working in staging but not production, it's because some change has not been approved and published. If you look through your approval tab in DTM, do you see data elements or rules that are related to this project that still need to be approved?
Secondly, you may need to check your publish queue. If there are items in the publish queue that are related to this project, they will need to be published in addition to approved before they will be reflected in the production library.
Hopefully this helps.
- Jantzen