You can look in the dipstick hole with the engine running and there should be a good flow along the frame and down the hole . That will tell you if the oil pumps are working.
there is an oil line update that some of the dales needed. for some reason the stock routing builds up a lot of pressure and blows the oil out the breather, and that makes it flood out the air box. just an idea.
Another thing that is only touched on is if you rolled the quad it can cause a clog in the line and force it out too. One thing I have done in the past is blow compressed air down the vent hole with the drain plug out you should hear air coming out.