I’ve found a workable workaround, I uninstalled the Plex app on fire stick and disabled auto app updates. I found the apk 6.12, which is supposed to be a stable version that works well, and downloaded and installed it and lo and behold the Plex app on fire stick will direct play the files. I’m going to look for a more recent version that works tomorrow. I don’t really like this UI. Anyone know where you can find old Plex amazon apks.
Here is proof it works. 
