Had a portrait shoot two Saturdays ago. Loaded the Portra into my M645J and the windon just kept going through the roll as if I had the M/E switch activated (I didn't). Then ran a roll of TMax right behind it, no problem. I know it's not the film, but have any of you guys had an intermittent prob such as this? First time it happened. Hope it never happens again. Any advice woul;d be good. Thank you.