Cold as in you did not "move" the RV from where you parked it the night before?
If so those were the "last known" readings from the night before.
Sensors are designed to "go to sleep" when the wheels top turning after a preset amount of time.
You typically need to drive for 10-20 minutes above 20 MPH to "wake up" the sensors. Once woke up they will report the updated readings to your display.
As far as pressures not being "even", this happens a lot when you have one side exposed to a higher temp as the sun hits it. Even just a little more direct sun on one side can heat the air in the tires on that side enough to give 5 lbs or higher pressure reading.
You almost need to check the pressures when it is overcast, early in morning or later at night or whenever you have less direct sun hitting any of the tires.