[flybouy]

Sounds like coil freeze over. Several things can cause this. Most commonly:

Dirty air filter - this inhibits air flow over the coils.
Dirty coils - typically from not cleaning the filter.
Low fan speed - RVs are a challenging environment. Fan should be set to high and run continuously.
Insufficiant cooling for the conditions. I.E. too much humidity because the doors are open too often or for too long. The a/c isn't designed to cool the great outdoors.

Mechanical causes:
Freeze sensor not properly adjusted. Unlikely to happen to both units but possible.
Low refridgerant charge, again unlikely to happen to both units simultaneously.