I found some moisture today when I did an oil change right where you add the oil. Is this common, I looked at the rubber seal and everything looked okay.

 

Yea Mositure in the fill cap is always pretty normal on vehicles i have a buddy with and 05 whose got the moisture under the cap and i work for hummer bentley and rolls royce and they all do the same thing.ive seen it on every car.

 

If you drive short trips all the time, then yes it's normal. I had the same thing and the dealership said it takes roughly 18 miles to warm up enough to burn all the condensation out.