Over the holiday I found 8 rolls of 120 on two sheets of glassine. About 8 years old.
Some of the negs had been improperly fixed, some had photoflo residue. The crud on some strips transferred onto adjacent strips.
Same thing would be expected of any speck of dust... Each speck would affect two strips of film - the one it stuck to and the one it dented.
They are not stuck together, or "ruined" but I would have been happier if they had been in their own sleeves.