yosip1115

I thought the one hose going into your catch can was from the pcv valve.

If it's pushing that much oil out of the valve cover there is a problem, obviously. You can figure out which bank it is by taking off the hose connecting them and blocking off the rear drivers side port.

If they modified the valve cover then consider that it could be blowby from the crankcase. If not then yeah something like a valve seal is leaking combustion gas.

Do a leakdown

Edit:
I believe I'm wrong about the valve cover venting being separate from the PCV system. It doesn't really change much about this discussion, but I'm going to verify that the PCV valve simply goes into the passenger side valve cover when I get a chance to. I see a path on the passenger side head that goes down to the crankcase, and that explains why it affects idle when the oil cap is taken off.

If that is the case, then you may see a benefit by switching your catch can over to the PCV valve like everyone else has it.

Internal baffling in the valve cover could be a potential difference between those two ports.