The solution has been offered. The reason behind the "feature" is that some air conditioners can also have a heat strip installed. This heating element means your air conditioner can be used as a heater as well, so you'd want your thermostat to to turn the air con fan on when used in this manner. The other train of thought is that running the air con fan will circulate the air within the camper more efficiently so that the furnace will heat up the interior more quickly.
2012 Aspen Trail 2710BH | 280 watts of solar on the roof | 2x6V GC batteries | 100% LED lighting | 1500 & 300 watt PSW inverters | so far strictly boondocking