Jitsi Meet does not respect video parameters

Jitsi seems to have a number of settings to control the quality of video calls, but on my server they are being taken as suggestions at best. For instance, I have set the minimum frame rate to 20; even in a call with only 4 test instances, it almost never goes above 15. I have set the screen sharing FPS to 30; it goes to 10 or lower. I have set the minimum height to 720p, but it happily goes below that, and rarely goes to the ideal value. I have even disabled simulcast, just in case, but no luck. All this even when the load on each CPU is less than 25% and there is plenty of bandwidth and RAM to spare. On somewhat larger calls (10+) the frame rate drops even further and the E2E RTT tends to spike, but even on smaller calls it does not seem to prioritize the assigned values.

What could be causing this? I would think it would be trivial to fix. Presumably this is not intended behavior?