I'm the poster of "Videos stop loading after visiting many scenes".
Our project has 15 videos. All videos are in persitent symbols.
Playing video's is triggered with JS, not autoplaying.
We did extensive testing on this and it appears to be a memory issue:
-playing more than 15 video's triggered the behaviour
-also, loading scenes containing the videos triggered the behaviour after about 30 scenes, even if the video's were not playing.
-Going back and forth between 2 scenes containing video also triggered the behaviour after 30 accumalative scene loads
We were not able to fix the issue.
In the end this was our workaround:
-a scene-counter (for mobile only) that reloads the whole project to the current scene after 30 scenes or 14 video-plays
-"create offline application cache" is used, so that reloading times arre acceptable.
Hope that helps (a bit).