Suppose two clients, with resources A and B are both joined to a chatroom.

If B attempts to rejoin (ie, send a MUC join when already joined), the code first checks for a nick-share possibility by comparing the first listed MUCRole's bare jid with B's bare jid, which matches.

To check for rejoins, the code checks to see if the occupant has the same bare jid - if the first listed occupant is A, this fails, however the client is already joined, and so errors will occur later.