It appears that the Cyrus upgrade broke the ‘keyword’ functionality which we use for flagging messages for delete and move. This means that they’ve been working indifferently depending on how lucky you happen to be (interestingly, my personal account has had no problem, and neither have any of our test accounts – but I have replicated it very easy with other people’s accounts)
I am reverting Cyrus back to the previous installed copy. This will require another restart on all servers, sorry.
Bron.