Google "Shutter Capping." Usually happening at 1/500 and 1/1000 for focal plane shutters. Try exercising the shutter from 1/125 and up; I did my Canon FTB about 50 times at each speed and it loosened up and I haven't seen the problem since.
+1. Definitely underexposed with hot highlights. Add a stop or two more exposure and cut development in half or double the dilution at the same development time.
<p>With the mode dial set to 'P' and the lens set to a fixed aperture, the 'M' light comes on but the camera continues to operate in P mode. At least that is the way mine operates. </p>