Brake System light revisited

OK so here's the deal. Do this with the key on. You'll need 2 people. First crack one of the rear bleeders loose and push and hold the brake pedal down. Tighten the bleeder and release the pedal. Now go to the front wheel and crack the bleeder and slowly push the pedal down till the light goes out and stop! Tighten the bleeder and release the pedal. Fixed. You just centered the valve
Agreed this will center the valve BUT...

It is supposed to be self centering, so why is it not self centering?

And then why is it moving when the brakes applied?

Something is wrong