Moderator couldn't hear or see 11th participant

I have a self-hosted system and participated in a call today with 11 members (10 members + moderator). Audio only, no video. The moderator could not see the 11th caller’s tile and could not hear the 11th caller, yet everyone else could hear and speak to the 11th caller and could see 11th caller’s tile. Then, one of the callers dropped off the meeting (so now there were 10 participants) and the caller who couldn’t be heard by the moderator dropped off and re-entered the meeting and then could be heard by the moderator (as well as everyone else as before).

The system load was VERY low during the call so resources don’t appear to be a contributing factor.

I see that Jitsi should be able to handle up to 75 callers.

Has anyone else had this problem? Any ideas on what could have caused this anomaly or how to address it?