I and the exact same condition arise with my 2020 Python.
As has been pointed out, there is a tiny “jam” nut on top of the front sight that needs to be tightened down to prevent it from moving under recoil.
The rear sight is not “click” adjustable for windage and the jam nut is what holds it in place as opposed to a detent in the sight mechanism.
Find a .050” Allen wrench, and once you’ve got the rear sight centered for the ammo your using “snug” it down.
Don’t over tighten that jam nut as it is so tiny it’ll surely strip.
Gratuitous pics of my 2020 Python
