I can't see anything with the Polaroid back itself that should be able to make the camera body act as you describes. Not even if something is broken/malfunctioning on the back.
The only thing I can think of that makes the RZ act like this is when you set the
switch on the lenses to "T" for "Time Exposure". Check that one.
It might be that you, by mistake, moved it when attaching the Polaroid back. Or even when
you took the camera out of the bag, or......
Something like once a year I somehow run into this moving the switch accidentally.
And it always takes me like a minute before I realize what the problem actually is.
