Possibly condensation due to colder water temps and high humidity at that stop?
Also if there is excessive pressure built up in your Airstream water system from thermal expansion, a leak may be forced. The system is designed to have a bubble of air in the top of the water heater to take up this expansion, often the bubble is lost and needs to be restored.
Doug and Cheryl
2012 FC RB, Michelin 16, ProPride 1400
2016 Ram 1500 Laramie Crew Cab 4X4 Ecodiesel 3.92 axles
The Truth is More Important Than the Facts