I expected to see at least accelerometer model.
In general, that is not normal. For 'click' (or 'tap') detection usually 2-3 parameters are used:
- threshold value for acceleration slope (not the acceleration itself);
- shock time (clicking is very fast motion, so the acceleration change must cease before the shock time ends);
- quiet time (for double-click recognition).
In your case I presume your shock time is too big, so shaking causes the accelerometer to see it as 'click'. But that is only my assumption. It depends on the accelerometer model, settings and your mechanic part.