ridebmx
Newbie
I don't think it's the thing to worry about. I have the same on my M2 and i've already shot 15 rolls with no problem.
payasam
a.k.a. Mukul Dube
I had a problem with a IIIc which another RFF member said recently was common with M models: light shields allowing light to go past and hit the film when no lens is mounted. Simple to check. In fairly bright light (not direct sunlight), remove the lens and replace it after a few seconds. Remember the frame number in the gate at the time. Leakage will show up when the film is developed.