On my motor I sometimes have the oil tank drip but when I do this is what happens:
When tilted up, some oil leaks out of the cap on the main tank sensor. That oil pools in the bottom of the cowling but does not leak out into the motor well UNTIL the motor is tilted down. Even then, it can take some time.
Other than replacing the sensor which is pretty expensive, I have found that popping the sensor can and cleaning the inside lip as well as the lip on the tank helps. Turning the cap to a different orientation can help. Putting a tie wrap around the cap may help too.
After all these years of on and off leaks, I just clean up the oil in the motor well and go fishing.