Left/Right windage adjustments not working on crossbow scope?

Shot about 20 times this afternoon, was shooting left of bullseye about 4 inches, rotated several clicks in the R direction on my windage knob. The only thing that worked was tapping on the scope top as this would then make the arrow shoot where I was aiming, bullseye, but after a shot or two was back to shooting 4 inches to the left.

Scope is properly mounted and there is no wiggle or play, any ideas what this could be? I am now maxed out on my left/right windage knob (in the right direction) but I am still shooting about 4 inches to the left and the tapping no longer does anything.