If the film came out of the fridge too quick and adhered to the pressure plate this would be a possible are to look, it does look like something is stuck to the film or making a direct impression

I have never seen any thing like this and would be interested how this plays out.
Quote Originally Posted by Thomas Bertilsson View Post
The pressure plate on my Pentax KX has a pattern on it very similar to the 'fabric' pattern showing in your negatives.

But I agree to test the changing bag for light leaks.