If it leaked when it was stationary and the fridge was off, then it has to be somewhere on the body/rivet/door.
If you didn't notice if it did this when in transit, then when the weather gets better, take a hose and spay water around the well. If the floor gets wet, you found the culprit.
I did a light test and the water test in the wheel well. Light test passed, but water test failed. In my case, the trailer could go through a monsoon when standing still and no issues....however when in transit in rain, the wheels would kick up water into a place where they forgot to caulk. Once I caulked it, there were no further issues.