I also see this exact behavior on my Nvidia Shield TV at your same software levels. In general, the Live TV Picture-in-Picture (PIP) for OTA channels doesn’t work with my android Tv based Nvidia Shield, HDHomeRun tuner and Plex app. However, PIP does work w/Plex on my ROKU streamer. I reported issue with this post :
There is not much indication on this “LiveTV and DVR” forum that the Plex developers have time to address or acknowledge many of the reported bugs.
