Persistent 'water in charging port' warning on iPhone despite no moisture

My iPhone, all of a sudden, constantly receives the ‘water in charging port’ warning out of absolutely nowhere. Constantly.

most recently, I went to sleep with no issues when putting my phone on charge. I was woken up by the sound that comes from the phone when the charging port was wet, but yet again— I hadn’t touched the phone (as I was asleep).

It surely can’t be from the charger port actually having moisture in it? I’ve reset the phone multiple times, I’ve used different wires, and I’ve used non-abrasive brushes and small toothpicks to clean the area out, but the issue persists.

[Re-Titled by Moderator]

Original Title: Charger port issue.