Well, it’s not a bug, but more of a very bad workflow.
In 4.13 I changed it so you won’t accidentally play videos. In particular…
- Any open media player editors will stop playback when PIE/SIE starts
- In the game, playback has to be started explicitly via BP
- When PIE/SIE ends, all players are stopped and reset
Hopefully, with those changes, the user is in full control over what plays when.