I know – though it’s more a distance thing than a time thing, they don’t spawn if anyone is too close. The problem arises when people spread out, looking for enemies, while some hang out near the boss room. They can stop most or all of the rooms spawning, depending on how many people there are and the size of the Cland.
It’s easy to fix if everyone stays together, but the more people there are the more chance there is one or two who don’t understand or don’t care. You can TP to someone to reduce the number of rooms that are blocked, but the danger of that is you can’t then TP to a boss if it appears just at that moment (as has happened to me more than once) and there are leechers.