We have queue groups where members are not allowed to change their queue status. However, users have an option in their app to ACCEPT QUEUE CALLS, and if they tur that off...they do not get calls to the queue group.

This sounds like normal behavior. Disallowing changes to queue status means they can't toggle a specific queue on/off and is just always on when accepting queue calls. Unfortunately, there does not appear to be an option to hide/disable the accept queue calls toggle at the moment. You can vote for that in this thread: Allow disabling "Accept Queue Calls" under roles for | Community Ideas (ringcentral.com).