Are you shooting a few at least three shots with the new ammo before you shoot your groups that you are shooting on camera?
Often if not most of the time the first three or so shots when changing projectiles will not shoot true. Airgun barrels seem to need to be seasoned, to the new ammo, and after three or so shots, that most often change in POI, they will group their best.
You might give it a try and see if it makes a difference.