That is how it works, was the same on our Montana. But since you have a thermostat in the Bedroom, you should be able to set it's temp lower, close the doors and then it should cool down to the set temp. One advantage our Montana had, it had Dometic AC's with the Quick Kool feature, so you could open the dump register and put all the cold into the bedroom, but a draw back was the noise level, noisey.
Michelle & Ann
2018 Chevy 3500HD Crew Cab High Country DRW, D/A, 2016 RW39MB, Dual ACs, Auto Level, Auto Sat Dish, Stack W/D, King Sleep #, 17.5" Sailuns w/Disc, MORryde IS & Pin, Comfort Ride Hitch, 5.5 Onan, Res Fridge & Induction Cook Top