Originally posted by clickclick I'm thinking you fed lots of leader and/or advanced/released the shutter a few times more than necessary when you loaded it and did the initial wind on to the take up sprocket, and all this before shutting the back on the camera. Does this sound possible?
It definietly is. Stupid me loaded the cassette in upside down during the first attempt. After attempting to advance the film a couple of times while noticing that the mechanism was not working correctly, I readjusted it. It's very possible that some of the exposures were already out when this happened and I fed in some of the excess during the second try.