The Dometic CCC has 2 ways to sense temp on Zone 1
1. The wall tstat is the sensor. make sure the bottom where the bulb sensor is located does not have dust or debris on it
2. The sensor is on a wall like the Rear Zone 2 sensor. When this is installed it renders the tstat inop on sensing temp.
Odds are you have a tstat sensor problem. Respond if you have a wall sensor like the bedroom. Also, Some of the older Monaco built products installed that remote sensor up front by the drivers area and THAT would never be able to sense the true colder area behind the seat. Doug