It doesn't surprise me, when I took my CDL tests years ago the written tests addressed checking tire pressures when the tires were cold for this exact reason. I don't remember if it was in the CDL written information or somewhere else where it said don't adjust inflation pressures on hot tires.
I've even noticed a difference on tires that were on the sunny side of a trailer vs the shaded side of the trailer in the cold or hot months of the year. I would say keep watching them. I often use an IR temp gun to check trailer brakes and bearing temps. I figure if I have them all close in temperature after a trip then I probably have the bearings set right and the brakes aren't sticking. I have diagnosed bearings going out on various things by using the temp gun, it is very handy.
I've even noticed a difference on tires that were on the sunny side of a trailer vs the shaded side of the trailer in the cold or hot months of the year. I would say keep watching them. I often use an IR temp gun to check trailer brakes and bearing temps. I figure if I have them all close in temperature after a trip then I probably have the bearings set right and the brakes aren't sticking. I have diagnosed bearings going out on various things by using the temp gun, it is very handy.
