So it seems if a single monster is alerted, the whole room will do the same. So if you are invising and there is one champ with true seeing, it's like if the whole room had true seeing for spot purposes. It never made much sense to me the old mechanic that a monster would be alerted while his buddies not, but I just wanted to know if this is WAI. But if the idea was to make real world sense, get rid of dungeon alert, because it doesn't have any.
This is also causing alert on almost every single room you go in, even if you are clearing everything. Maybe with this new mechanic if you're not going to remove the alert, at least you may want to change the number of enemies that need to be alerted to cause green/yellow/orange/red alert.