A bit of an odd one this and it could be specific to the way mailboxes are configured in our environment.
I started to play with the new Calendar feature in 8.5 which allows you to subscribe to other peoples calendars including Goggle calendars. In this instance I was overlaying a colleagues Notes calendar and just to see what happened I attempted to delete one of his entries. NB Our production environment is still 6.03 hence the need to change versions.
Lo and behold I managed to delete his meeting from his calendar from within mine. My first reaction was to see how much havoc I could cause to his week aheadI want to point out this is not a bug with 8.5, it just highlighted the fact that his ACL was not correct. Even though his default access was set to No Access, he had the write public documents enabled.
To prove the point I opened his calendar from within my 6 client and deleted another entry. At this point he asked me to think about deleting old meetings not future ones
This seems to be a historic problem as recent mailboxes have the ACL correctly set.
One more task for the 8.5 migration project.
It just goes to show you what great new features may impact in your enviroment.