I have a situation where I have a pseudo administration role that is not an administrator to meet certain internal organization needs. After the last AGOL update, that role no longer is able to change the sharing settings on an item that is not owned by them, even though they have the rights to be able to do so. The only permissions I left out were the following:
Everything else they can do.
Ironically, if I turned all those permissions on, they still would not be able to change the sharing settings on items not owned by them. I have actually have to switch the affected users to be Administrators to be able to fix this.
The behavior I see is that they do not receive an error when they attempt to change permissions. Instead, it gives them the green success box, but then nothing changes on the item.
Not a great situation when trying to implement the least privileges' model.