Everytime a PAM Admin attempts to remove a Device from a Group, saves it successfully.
Get's the message -> Confirmation: PAM-UI-1500: Device Saved.
However if they go back in, the Device Group is never removed.
The root cause is because the PAM Admin had Device Tags defined at the Device Group Level:
(PAM UI >> Devices >> Manage Device Groups >> Open on that you are trying to remove >> Go into the Tags Tab)
If using Devices Tags, you first must remove the Tag on the Device and than it will removed from the Group.