I started always cutting the film because I observed this discharge about 30 years ago and it would fog the film. Recently, though, I noticed if you peel the tape slowly you can be OK. This pertains to re-spooling 120 to 620 rolls, where you need to release the tape and re-stick it.
Could be stress fog too. Take a piece of unexposed film, and put a crease in it. Develop the film. Bet you see some fog along the crease mark.