all of the time now I have the multiple exposure tabs on the side of my mirror, however the multiple exposure lever is not set to multiple exposure, yet the tabs on the side are there. Also the other switch is set to N and I'm still having the same thing appear.
I also don't understand how when I put a back on the camera it still works fine, just with the little tabs appearing, and the multiple exposure works as well.
I own an SQ-A, but I'm drawing a complete blank on the "little tabs" you refer to. Admittedly I've only used multi-exposure to give a quick check of a new lens or back without film.