Server Version#: 1.19.3.2764 (Windows 10 Pro)
Player Version#: 8.1.0.17759 (62cca614)
For what appears to be at random, my preroll video for movies occasionally only plays the audio with a black screen on both of my 2017 Nvidia Shields. If I stop and restart the movie, it will play the preroll properly. If I toggle the status from watched to unwatched, or vice versa, depending on the original status, the preroll plays properly.
There seems to be no distinct reason for when this will occur, and it ONLY occurs on the Nvidia Shield. Fine on Roku, Xbox One, Android mobile, Web Player, etc.