Michelin Tire Pressure

More of a case that slides make it overweight. I have a 26' with a queen not sandwiched in a corner but without slides. I've still got around 2100 lbs. left after being fully packed with the water and fuel tank full. Slides are a cargo capacity killer on mid to long C's.

The "truck" version of the chart is PER AXLE. The "RV" version is by Corner LF, RF, LR, RR... They do this to affirm the finding that RV's tend to be loaded unevenly side to side. So they express Corners instead of Axles. And, Dual does not carry twice the load of a Single. Your front pressure would be 55-psi, and your rear axle is overloaded, so 80-psi there and try to shift weight forward.
Coach may not have enough wheelbase. This happens when a builder tries to but a walkaround queen rear bedroom on less than a 31-ft coach.

Have you had the RV weighed or are you only using the numbers off of the door sticker.

Your two front tires will support 2600lbs X 2 = 5200lbs total. So you are 1300lbs safe 5200 - 3900 = 1300lbs

Rear would be 4940 X 2 = 9880 so you are safe by only 180 lbs on the rear.

To make sure you are safe have the RV weighed to confirm all of the numbers.

In the meantime keep the tires inflated to the maximum of 80lbs.