Crank the idle-speed up,lol.
Kidding
They call that regulator creep.
Some carbs put up with it. It's like Gerald said.
But make sure your EFI rubber jumpers are solidly connected and cannot blow off. Try to imagine how dangerous even a few seconds of that Holley running WFO would be! I doubt you would catch it before your car erupts in flames.
Personally, I proba, no make that I would install a return line. And I would try to run the regulator after the carb, if that is possible..
