Nope. Not pre-menstrual. Plex Media Server.
After a few go-arounds with getting plex setup with Sonarr, I started running into issues with a bandwidth error message "Not enough bandwidth for playback". Ironically, I had another show on Plex that played fine.
TL;DR - Using ffmpeg to convert from mkv to mp4 files worked
The first file I downloaded was in mkv format. While troubleshooting, I converted this file to mp4. Then I had a systemd issue which caused me to re-install TinkerOS. After re-loading Plex, it picked up the show. I didn't realize at the time that I had two copies of the show from my ffmpeg output. Plex picked up the working mp4 version after re-install. Queue my next show getting loaded and I hit the dreaded bandwidth error. A quick conversion in ffmpeg and I'm off and running!