I placed a range of secret doors, that were all working independed. When I couldn't make them work on one side without the backside, I placed them all on one trigger_once. So that could be reason.
I can play the whole map (116 ent), untill the last stage, where an overload starts.
The reason is a Launcher_Touch that is in use with one of the baddies. If I delete the monster, another one complains again about its Laser_Touch.
Here are a screenshot and log.
overload
log