Question regardind little oil air filter

Hi all, i did change dsg filter so had to remove my air filter (ea888 gen4). There was a very little amount of oil on the connector of my filter.

Air filter was dry, could be that the previous owner used some oil to fit everything in place.

Anybody experienced something same or know what it could be?

Performance of the car is still on point, turbo and everything is working fine.

Anybody experienced this before?

Thanks in advance, regards Wouter