Recently I came across this issue. All of the sudden people would start losing access to places. Not everybody and not to all places.
You must love these problems where you can’t pinpoint any logic.
After some asking around, it turned out the Domino admin had been mass changing groups in the Domino ldap directory. this resulted in a changed level of nesting for some users in some groups. The nesting level got 1 to 3 levels deeper. I was not notified of this change.
By default Lotus Quickr allows a nesting level for groups of 4 levels deep. This is configured by a setting in the Quickr servers notes.ini:
Changing this setting and restarting the server caused all issues