Upon V11 update, I had a few emails sent out but not since then Seem like the notifications were a little crazy as well as it kept sending old activity but is okay now. I am not seeing any of the problems like 2, 3, 4 in your list.
they might be in q I've been getting as a user 3 days in a row emails. like me every user has been getting it, you can not know who gets what
