ANY running engine will produce some amount of blow~By..I think that is what you are seeing.
IF you don't have a PCV , Install one AND a vented breather cap..It will keep the Engine / Engine Bay cleaner, as well as the undercarriage, and garage floor..the oil will stay cleaner longer.
IF you do have a PCV, inspect it..(Rattle Check it) Then shoot a bunch of carb cleaner through it Be sure it's the right Valve for your Application also.
If it continues , or starts slinging oil, check your valve covers for Baffles, if none, install them.
If it's a FRESH engine the blow~By will settle down over time.
Have a HAPPY and SAFE
4 TH Of July!