I have replaced several felt "run channels" for this problem.
You could also have a faulty DCM like Gilly said. It monitors the
amperage required to operate the window. If amps climb, the pinch protection kicks in.
I would pull the fuses for all windows and put a fluke meter in place of the fuse to check amperage. Check the draw of each window up and down and compare.
If your l/r window draws more power than the r/r, you have a binding run strip or bad regulator / motor.
If amperage draw is consitant, you may have a bad DCM.
Your shop should be able to figure this one out.