Study the layout of the engine and you'll notice it's definitely "possible" for oil to be sucked into the intake ports...however it is not a very common problem, the OE seals are very stout pieces, I have even reused them before w/o any problems....but never say never.

There is a pcv passage on the right intake flange and a breather + oil filler flange on the left intake flange. Oil does pass directly through the intake, because there is nowhere else on the motor for breather/oil fill/pcv.

Intake may be cracked into one of the breather/filler/pcv passages. I have never heard of it happening, but that would definitely do it.