It could be a split nozzle, or maybe the nozzle is not sealing well enough against the body of the airbrush. Examine the nozzle closely with a magnifier to see if the tip is split. Then look at the other end of the nozzle and the hole in the airbrush and look for any scratches or particles of crud. If you don't see any problem, try a little bees wax on the edge of the opening in the airbrush body. I keep a little chunk of bees wax just for that purpose.
If your Patriot has the rubber O-ring between the head and the body, try removing it. It may be that you are not tightening the head enough to get a seal. Without the O-ring, finger tight should be enough.
Don