Regulator issues (ugh)

[SerialNoodle]

Hey guys, just need a little help.

When I put some air in my HPA tank (from empty), the pressure needle on my Balystik regulator will go past its normal operating pressure and creep up to the red zone, then starts slowly venting air out of the small vent hole in the side.
When I put my line into the regulator, the pressure goes down to 110 psi (normal operating pressure) then slowly creeps up. Same happens when it's plugged into a gun.

Everything looks fine, my o-rings aren't dry or damaged and there's no debris from what I can see. Any help would be appreciated. Thanks!