It's good to question everything. I'm not totally sure how this is possible either, hence why I was always under the impression the pcv valve was forced closed under boost (to avoid pressuring the valve cover). This is the service manual for the 2.0 T-GDI Theta II and the pages before/after the ones I previously provided show CAD of our engine bay/components including the turbo. Maybe Hyundai dropped the ball with the pcv diagram for this platform (which would be unfortunate). I am not 100% sure here, but it is the information provided by them for our engines. I see the pcv schematic table has a column for high load/acceleration but doesn't mention boost at all. As far as the vapors going through the breather tube , this scenario should happen when there is a high volume of blow-by (high load/acceleration). The built up blow-by should vent under its own pressure and with the help of a vacuum from the turbo (airbox/filter creates restriction leading to vacuum between airbox and turbo). So in this case the crankase would be venting ("breathing") all that excess blow-by coming from the cylinders. Under normal load/acceleration the fresh air coming from the breather is used to sweep the blow-by out of the system. Attached are the pages surrounding the pcv section showing CAD that matches our VN's
I have seen a few places in the service manuals where non-N vehicles are shown. Certainly I can see vacuum at the point where the breather attaches to the intake, but the blow by flow into the case permitting flow back up the breather completes the picture. Looking back it should have been pretty obvious...
Keep us posted on your catch can contents