I doubt it would be an over oiled filter tbh as before your throttle body got dirty your maf would probably have a hissy fit. The pcv takes oil fumes from the crankcase.
Do they not get oiled up becaus of the pcv?
Dunno mate - never heard of a pcv but I was told when Carla's looked a bit mucky that I'd probably over oiled the popcharger.
Perhaps both?