unfortunately, I don’t have any experience with update_row or delete_row and I’d say that you’re problems are definitely due to having nested repeaters. More than likely the nesting will need to be reflected in the $selector argument, but I don’t really know for sure.
You might get more help if you open a support ticket on this issue and see if they can help you. https://support.advancedcustomfields.com/new-ticket/
Please post anything you find here since it will help others with the same problem.
