As a build 738 there is a new bug that seems to be affecting buffered triggers.
If a player responsible for activating a buffered trigger leaves the instance, new joins will not replay the trigger.
World Name: Bedroom Theatre
Player A and B Join the map.
Player A selects one of the video players. Doing so does a number of things, one easily visible change is the volume controls turning on by the table.
Player A leaves the map.
Any player who joins the map will now see the room in the state as if no video player has been selected, such as there being no visible volume controls.
This also affects every other buffered trigger in the above map, such as unlocking controls of the video player to everyone, buffered states of the video player such as aspect ratio, 2d/3d mode etc.
The triggers in question are of AlwaysBufferOne type.
Error is also present in the error log as provided in the screenshot.
This seems to also affect the buffered setplaylist as part of the seturl function of video players, throwing similar errors indicating instigator not found.