I know its cheesy but AI created this list of potential causes for high crankcase pressure. Of course if that is what is actually going on here, seems plausible to force oil up and out of the PCV that way, but of course verify.
Worn piston rings or cylinder walls:
As engine components wear over time, gaps between piston rings and cylinder walls can increase, allowing more combustion gases to leak into the crankcase (known as blow-by).
Blocked or malfunctioning exhaust gas recirculation (EGR) system:
A blocked EGR system can allow pressure to build up in the crankcase.
Leaking turbocharger oil seals:
Faulty turbo seals can allow compressed air to leak into the turbo oil drain, pressurizing the crankcase.
Clogged or inadequate crankcase ventilation system:
A blocked PCV valve, oil separator, or ventilation hoses can prevent proper venting of crankcase gases.
Head gasket issues:
A failing head gasket can allow combustion gases to enter the crankcase.
Carbon buildup:
Carbon deposits can cause piston rings to stick in their grooves, leading to increased blow-by.
Turbocharger issues:
A malfunctioning turbocharger can potentially force compressed air into the engine's oil system, increasing crankcase pressure.
Inadequate oil drain back from the turbocharger:
If oil cannot drain properly from the turbo back to the engine, it can contribute to increased crankcase pressure.