Was this issue ever resolved? I also get the same errors when the DVR is actually recording something:
Line 559 : Jun 25, 2018 20:28:50.951 [14540] ERROR - Caught exception trying to stream file: C:\Plex\temp\Transcode\Sessions\plex-transcode-f14b6fc2-5cc9-40d8-a87d-7da2525e34cf\media-01353.ts: write: A request to send or receive data was disallowed because the socket had already been shut down in that direction with a previous shutdown call
Clearing loose ends. These errors were caused by bug in Microsoft Windows Update released on 10th July 2018 and resolved by further update on 16th July 2018.
We have now discovered that the following specific transcoder errors may also arise due to Malwarebytes Premium blocking some localhost Plex Transcoder requests.
A Support Article has now been published for this problem
The specific errors this relates to is this error together with other errors