I've noticed that if you attach a trigger to a room that was created with buildwalk and that trigger contains the 'wait' command, EVENTFUNC(trig_wait_event) will log "Trigger restart attempt on unknown entity." and the script doesn't run.
I think this points to buildwalk not entering the new room into the global room list correctly? It's beyond my skills though
How long had the room existed? If it was a new room, had saveall been done? A lot of builders build with buildwalk and a lot of those rooms have triggers put on them. That's why I'm wondering about the timeline.