Fuel leak

[Gene563]

I had a strange situation the other day; I had a random fuel leak from my otherwise dry scoot.
I took the bike out for a short ride and when I returned, parked it on the side stand. A short while later, I noticed a puddle of gas; I traced it to the fuel sending unit. I had recently filled it and typically keep it on the center stand. I dried up the fuel, tapped the retaining ring on the sender to ensure tightness, and haven't seen any leakage return.
I'm wondering if I over-filled the tank and the tilt from the side stand caused it to leak. What type of gasket does the sender use and would they be prone to leak? Has anyone else experienced anything like this?

Thanks,
Gene