I've been having issues ever since i updated to the latest plugin. Plex fails majority of the time with similar errors. I've tried optimizing and cleaning up plex database prior to doing a manual update and it will give me a similar failure. Also tried deleting the offending file that it calls out but it then fails with a different file. Only source file I have backing up is /mnt/cache/appdata. For Plex specfically, i have /mnt/cache/appdata/plex as internal. My temp transcode and media folder is set as excluded.