Server Version#: 1.30.0.6486-629d58034
Player Version#: 9.13.1
When using a Movie pre-roll video under Settings > Extras in the server settings and then playing a movie on a mobile android device or an android TV device (NVIDIA Shield TV Pro/Chromecast with Google TV), the movie will being playing for 3-5 seconds, stop, and then it will play the pre-roll video.
This is not the intended result of this feature. When playing a movie with this feature enabled, Plex should immediately being playing the pre-roll video before trying to play the movie.
Bonus points if Plex can begin loading the movie in the background while the pre-roll video is playing, but that’s really not the point of this post.