My Bronica SQ-A seems to have a bit of a problem with shutter speed consistency. Taking off the film back and firing the shutter at random speeds, it's pretty obvious that every so often the shutter just does what it wants to, rather than what I ask it to. I noticed this today on a roll that I developed.

Any advice? I know the shutter is in the lens, so I hope I'm not going to have to drop any serious cash to get this fixed.

EDIT: It appears to be doing this with multiple lenses. And on both of my SQ bodies. Geez. I hope that leaving them unused for a while didn't hurt them. I did not close the shutters as is recommended.