This is something I have noticed for years -- though I also assumed it was static. I find that it does usually expose the film, but just right where the tape was stuck to the film. In theory, that end of the 120 roll should have no expose and be blank. But when I have noticed the light generated by removing the tape, I have also noticed some exposure density on the film only where the tape was...sort of a ghost image of the tape.

I have a bunch of 120 to develop...several different brands (Kodak, Ilford and Fuji). So I will do a little experimenting with tape removal! Film at 11