Home wiring issues (this is really strange)?

I know my way around electricity and installing and repairing circuits, lines, outlets, and fixtures, but I am not an electrician. I was trying to figure out what was going on while trying to get a hall fixture working again at my mom's. It comes out of a panel with 3 switches all wired together but it a 3-way switch to the fixture then to another switch and that's the end of the circuit. The other two seem to work normally. The third switch, the one in question, has a voltage of about 90-92 V across it and I have NO idea how that can be (both hots read the same). What could this possibly be? There doesn't seem to be any noticeable corrosion and the other fixtures, outlets on the circuit seem to be working properly. I will say, there is a fluorescent light behind a curtain box that comes out of the same switch panel, and it was bouncing all over the place, but the lights work fine and steadily. Should I try switching those or maybe disconnect them and see if I can get a normal, steady voltage on the hallway fixture?