q_
unfortunately a simple yarn/Yak job hasn't been able to conquer it.
I've been inside there 3-4 times and a now deceased respected FSU repairman couldn't fix it either.

It's the dreaded advance spool sprocket problem... I have tried the Kiev Survival page that deals with this problem specifically to no avail.
It's really a shame because the shutter is good and rest of the camera is in nice shape.
No leak in subdued light but get out in some harsh sun and you're baked. Same spot in the middle, bottom of the frame every time. Anywhere from a slight flare to a full blown starburst effect emanating from the bottom of the frame (top when in camera)
I gave up.