Panorama mask sometimes stuck

Question

My camera is the TVS I with the panorama function. I've had one film partly spoiled because one part of the panorama mask stuck in the panorama mode position even though I didn't want the panorama function for most of the photos on the film. Of course I didn't realise the problem until I saw the negatives.I've since run another 10 films through the camera (while I finished my holiday) and the problem did not recur. I'd really like to know that it's fixed though so I don't have any more surprises.If the panorama masks could be permanently disabled, that would be an adequate fix for me - I can create any panoramas I need by cropping a full frame.