My "new" Canon FT QL has a problem w/ the film spacing. On one of the frames toward the end it didn't advance all the way and I had a half frame double exposure. All the rest of the negs came out fine. Years ago I had another FT QL and it did the same thing now and then. Any ideas? I was guessing that it might have something to do w/ the Quick Load mechanism but don't see how, as it happened around frame 17 or 18.