Holley/Demon Carb stumble

It's a demon carb, has three notch in the side of the glass center one is in the middle of the sight glass.
I have a 650 holley, agree pull plug out off bowl and bump the fender, fuel dribble out your good, Demon is not this way.
If this fuel level was the problem it would have been the problem 2 years ago when i rebuilt it.