MP valve covers knock out machined for pcv grommet (Chevy style)

I installed the Catch Can today. I have a baffle 3/4" below my PCV, so anything I'm picking up is vaporized mostly. After driving about 20 miles and "getting on it" 3 or 4 times, I pulled the canister off and there was a small puddle of oil in the bottom. This engine has about 800 miles on it. I hope this gets better but I am convinced that adding this catch can is going to help my preignition situation and keep the engine cleaner.

Is this a problem more associated with Mopars? I've never noticed a problem with my SBC's. Thanks again for the recommendation.