Could a clogged pcv cause oil to seep past the oil retaining rings and into the combustion area?

 

never actually seen one clog up so rather unlikely, the more likely chance is the oil control seals flattened out over time and are allowing oil pressure by the rotors and into the engine.

a simple test would be just disconnect the vent from your oil filler tube and let the crankcase breathe to atmosphere, if the problem isn't resolved with a few engine warmup cycles, the issue is the oil control seals, or turbo turbine shaft seal if you are referring to a TII. only way to tell if it is the turbo is by removing the turbo after starting the engine cold and shutting it right back off and seeing if there is oil either after the turbine or at the exhaust ports. in/out play of a turbine shaft is also a pretty good indicator your turbo is smoked.