Leica R4S diagnostics time

[valdas]

Just something out of left field, but could it be possible that a tiny grub or worm has entered your camera's shutter box?
I've been in the automotive industry and have seen these get into the wierdest places.

Oh, I had this once - it was a small spider 🙂

https://www.rangefinderforum.com/forums/showthread.php?t=157577&highlight=Spider

 

[CharlesDAMorgan]

No visible spider or grub, but the possibilities are becoming entertaining.

I'm putting a self loaded film in today for a quick test. First will be with film window un-taped, then if light leaks show, I'll put another through with tape over the window. And do a slo mo, when I have the time.