I have had this issue as of today. I was watching a movie via plex.tv and it started to buffer. I stopped the playback and refreshed the page and was greeted with an unable to load page. Looked in my logs and there were tons of these entries. Seems to work fine for a while, then throw a bunch of these errors, crash the container and then reloads. During this instance, I manually restarted the docker to finish watching my movie.
My transcode setting is set to /transcode within Plex and it is pointing to a dedicated share in the docker configuration.