Hi @bluegeek9
This is from memory - the issue was on a client site that I'm no longer involved with...
* Is the issue sporadic or consistent?
Consistent, but there's some kind of trigger - it typically worked the first time. The site had a lot of group mappings set up (30+ maybe). Adding a mapping worked the first time, but no more.
ISTR that it would return to a working state after config export/import, even though a new mapping could have been added.
I did a bit of investigation, and concluded that something was invalid/broken in the FAPI structure obtained by ajax updates triggered by the the "add" button.
In the end I added a work-around - using a form_alter hook, added a number of empty rows to the form before display. With that it was possible to add new mappings.
Hope this info is of use, right now I'm not working with this module.