Today I added a new AD group to "Viewers".
After that, I ran the machine policy retrieval on my client on which I previously removed a group. After I ran this, de ConfigMgr Remote Control Users group was filled again. This time with 3 AD groups. So the group I removed before was added again and my new
group was also added.
Conclusion; if I make a change to the Default Client Settings it will push all the settings again to a client. But if you make a change locally, like removing a group, SCCM won't update this group again. It seems it doesn't do a verify on local settings
unless something has changed in SCCM itself. Indeed it seems to imply a bug.