I agree, which is why I pulled it off to look at it. The reason I didn't think it to be the issue was there was absolutely no oil residue inside the intake runner on the head. Just oil resting on the valve
That may be only because you have very little reversion, or the fuel is washing down the runner.
Not saying it couldn’t possibly be a stem seal, just highly unlikely IMO.
That much oil running down the stem after shutdown just doesn’t make sense.