I've reviewed the code and tried to replicate the issue. I was able to confirm that list of occupants was presenting invalid avatars (missing avatars) and I've fixed that. Moreover, I've encountered weird issues with this room - I've received only some presences for occupants in the room (the different set that for the same room connected from a different account). This looks like an issue with the delivery (or sending) of the presence of MUC occupants for this room. It is worth to note that this room is huge so some throttling or S2S issues could be also causing this.

I've encountered this issue twice, but during the rest of my test runs it was working without any issues.

Thank you, it works way better.

This looks like an issue with the delivery (or sending) of the presence of MUC occupants for this room. It is worth to note that this room is huge so some throttling or S2S issues could be also causing this.

Seemed plausible. I checked our code and if it were on our end it would have generated a WARNING (see https://github.com/tigase/tigase-server/blob/f109ec8676d0a63c71cd0009c4d97c50a1b28d63/src/main/java/tigase/server/ConnectionManager.java#L229-L229) so I'd assume that would have to be other server doing throttling. I vaguely remember that ejabberd was doing that but I don't know conversations.im configuration.