Does the door sticker on your 2500 show a "Light load" tire pressure range? Looks like they did away with the "Light load tire pressure" button like my 2013 has, but if you have a light load pressure listed on your door sticker, try setting your rear tires to that, the TPMS may be unhappy because the pressure is between the loaded pressure and the light load pressure.
The truck will ride much nicer, if I recall correctly it's 48 PSI on my 2013 Ram 2500 for the rear tires under light load conditions. My tires have 26000 miles on them now, and the wear is even.
Only fun is when you rotate the tires, they have to change the pressure in all four tires, and you have to drive a bit for the TPMS to re-detect which tire is where.
