We’re running 3.8.2 Alpha w/ Hazelcast (2 node). We’ve noticed that within MUCs there are numerous occasions when users are in the MUC, but their presence information is not distributed to all other users in the same MUC. It’s not consistent, however user A who can’t see user B in the MUC are always connected to different nodes.
Admin console on both nodes lists the same users in the MUC, so seems to be something with OF sending presence rather than actually joining. It also does not stop users communicating with each other in the MUC.