Having played a lot of paintball in the past (yes, this is related), I've done my fair share of breaking down/cleaning out pressure regulators.
I know that you've said it's fixed, and that's great. But, for other people reading this tread, absolutely do not in any way "block" the pressure relief valve to stop it from leaking.
Chances are there could have been a small grain of gunk or something else that you did not see when you took the regulator apart that came out. I've had something like a single grain of sand prevent regulators from working properly in the past.
I know the output pressures from these regulators are low, comparatively speaking, but the pressures going into them still need to be respected.