The next step would be to capture all the responses the Plex web (hosted app) is getting from the server from start of playback (tuning The channel ) up to time getting one of these warnings in the server log - so would be browser dev console network logging with preserve log option ticked and saving all the captured requests and responses into a .har file and zipped sent privately as PM together with the debug server logs
The development team have been trying to reproduce the problem but May be it happens on siecific channels
