I just got a used RZ67 kit. I really like this camera.

I was out shooting my first roll of film last night and encountered a problem: when the back is in normal (landscape) mode, the exposure detection (don't know technical name, but the red bar that indicates film has been exposed) only works intermittently. I see the red bar flash for a split second but it does not stay. Then the camera cocks but the film does not move. If I switch into 'M' mode and re-cock and shoot a few times it will finally take. The weird thing is that if I rotate the back 90° it works perfectly.

I have switched the camera into emergency mode so I could watch the pins to make sure they are both popping out when the shutter is tripped, and they are. I can't see any physical reason this should be happening, nor do I know of any electrical connection that has a bearing on this. It doesn't seem like the back is at fault if it works when turned to portrait mode.

Has anyone ever had this issue? Is there any adjustment or something I can check for? I've searched the forums and internet in vain for this specific issue. Everything else is working perfectly on the camera and it appears to be in very good shape. I can send back to KEH if necessary but obviously I'd rather not if it's something silly that I've overlooked.