My phone got some splash water. Unfortunately some water drops landed in the usb charging port. The phone gave me the error message that it detected moisture and i should dry it.
At some point the phone died because of low battery. I did not have charged it yet because of the concernings that the water and charging could damage the phone.
UPDATE: i used paper towels and let it dry overnight. I charged and there was no warnings.
I had this happen with a phone. It complained about moisture in the charging port for a few weeks whenever plugged in to charge, though after that, would charge for a while before complaining. The charging periods got longer and complaints rarer. The last one was a few months after the incident, and weeks after the previous complaint.