GF670 / Bessa III framing issue
So using my GF670 more frequently lately and have encountered a consistent problem. When I load the film, I have the "start" + arrows on the backing paper line up to the 6x6 mark on the camera, lock in both film rolls, pull it taut and close and then advance the film until it stops and locks at "1" on the film counter. So far so good and I shoot through the twelve exposures, with the film counter advancing as it should.
However, all of my last rolls have come out with only 11 exposures, with what I believe is the first exposure cut by the masking tape at the end of the roll and extra blank space on the developed negative. Which means that the exposure counter is locking prematurely (or late, if I have gotten wrong which end of the film this is).
Any idea why this would be happening? The film in question has generally been Arista Edu (repackaged Fomapan) of different speeds.
As always appreciate your insights and collective wisdom!