The room cap is only being applied when the population in the room is equal to the cap. If it exceeds the cap, spawning starts again.
e.g. while engaging a lone critter, a Rare and friend spawn, if a critter is not killed before the next spawn pulse, and since Rares very often bellow for 20s with their first action this happens quite a lot, spawning continues because there are 3 in the room.
e.g. if two critters are being engaged no more will spawn, but if one walks in from a neighbouring room, spawning restarts, because there are now 3 in the room.
Its repeatable. I set both those situations up and as soon as the room had 3 rather than 2 critters in it, it started spawning again.
it might be as simple as .EQ. in the code where it ought to be .GE. (or whatever the newfangled coding is for that) but something is having that effect and its nigh on impossible to progress in Reim unless I'm the only player in there. Even then there'll be one or two areas where there's a major delay due to the spawning of the Rare taking the room to 3 critters and continuing spawn.