Were you measuring the 85v at the screw on the left switch where both the incoming hot and jumper to the right switch are ?
Or were you measuring the 85v at the screw with the wire going to the light ?
Red lead top, common lead bottom(hot and jumper), still learning how to use a meter so that could be wrong as well but I did the same on the other switch and showed 121 volts so I assumed I was doing it correctly.