I can confirm this issue. I am running similar set up to OP. Intel Core i7 8559U processor with Quick Sync, using the Docker container. Hardware encoding on. This particular stream is SRT and it’s converting to ASS. 100% utilization of 1 logical CPU.
I have captured logs with Verbose + Debug turned on. I am happy to provide it so you can forward it to your engineering team. Just say the word.
Running Ubuntu 18.04, and Plex Server 1.15.4.993. Please continue to keep us updated on any response back from your development team. I find it odd that you do not have any way to communicate with them on updates for issues like this. I think they should be more transparent on a time line for a fix.
