Occasionally this is due to temperature changes around the phone such as weather conditions @siobhanw
Condensation can occur.
It's not always due to direct water exposure.
It should clear up after 5 to 10 minutes but if not let a Samsung Experience Store or Samsung Service Centre have hands on with the phone.
Current Phone > Samsung Z Fold³ 5G.
It is a software glitch. I started to have the same message after installing the last update last night.
SHAME ON SAMSUNG!
I am losing confidence on Samsung phones. The usb charger glitch is on many Samsung models, and they do not care to solve it.