Lower unit leaking gear oil

For reasons I can not explain I removed the vent screw from my lower unit for about 20 seconds. The next day there was a puddle of gear oil and the leak was coming from under the prop and under the metal ring behind the prop, I believe it is the bearing case. I then changed the lower end oil and now I can see a little oil under that metal ring behind the prop but no leak. Is it possible that when I removed the vent screw it forced the oil to go somewhere since the drain screw was still in? Or do I have to worry about a seal leak? The oil was changed three months before I removed vent screw that day and saw the puddle the next day. Should I worry or is there an easy fix. Im not mechanical enough to do a pressure test.

Re: Lower unit leaking gear oil

Did you take both screws out when refilling?Are you filling from bottom screw till vent screw(top) overflows?Did you replace both screw gaskets with new ones and tighten securely?If you missed any of these steps you probably have air in system.