Two possible leaks. Solenoid vents or Cup seal. I assume Kansas has things well in hand, but I figured I'd chip in.
If it's coming from the left side of the marker, through those two slotted vents where the frame meets the body(or just blowing generally from the left side of the grip), then your noid is venting.
This means that you need to turn down your AOC/LPR so there isn't as much pressure to the noid.
If you have an AOC, I feel genuine pity for you, those things are a B*TCH! I went and bought an LPR adapter and a Rock just so I wouldn't have to deal with it
If it is NOT a noid leak, there is the possibility that you have a cup seal that is not doing it's job very well, which would be the classic leak down the barrel. Either oil or replace it.