I saw this post but it seems to not have been resolved before the post was closed.
I have been having this issue for several months using Plex on a Samsung Smart TV, but the issue is not happening on Plex app on a Mac. I’m running Plex Server v1.15.4.919 on FreeNAS and Plex App v1.6.5.1097-3bb9dc68 on a Mac.