I just had an issue where users were directly added to the ACL of a folder. I created a group, added them to the group, added the group to the ACL of the folder and then removed the users and pressed apply. 18 of about 20 users were unaffected, but for some reason two users were denied access. I check the effective permissions tab and they were there. I added both users explicitly again. One of them still had an issue. I double checked offline files, but the data was not cached. I then had the other user restart their PC and the problem seemed to resolve itself after that. I have always seen permissions apply pretty much in real time. My questions are:
Why would this happen, especially since they were denied permission right away?
When does a user account authenticate?