We had a similar problem in June.
Elevation was the issue.
https://www.montanaowners.com/forums...rnace+limiting
Just curious, how cold was it?
For your model year (and mine 2019) there was a bad batch of control boards that would not work properly at freezing temperatures. One of our members troubleshoot and identified the problem by putting the boards in the freezer for a couple of hours then tested it. It didn't work. He put a hair dryer on it to warm it up and it started working. He went through several brand new boards that had the exact same issue.
BTW, the bedroom thermostat only runs the bedroom AC unit. However the thermostats are identical and can be swapped for troubleshooting.