I organized a 3+ hour call on 5 Sep 2020 from about 10:25 AM to 1:45 PM New York time zone.
With 10-11 participants most of whom shared their video, call quality was very good for the first 2 hours (or so). One user had a few audio issues that cleared up.
Even though a couple of participants had dropped out (and a couple of new ones joined) so there were only 8 or 9 participants in total, 2 or 3 users had increasingly distracting audio issues in the last hour.
It could have been feedback from one user with bad audio, but I don’t think so. Almost everyone was muted most of the time.
It could have been load issues or audio issues on their systems (they tended to be the users who were connected from almost the beginning).
It could have been meet.jit.si getting overloaded. But video and audio performance was generally good enough, that I’d guess it was bugs or performance issues on a couple of systems.
Recommendation: better testing for long lasting calls.
I will try to get better user reports, but that isn’t always easy.