Over the last 2 days but looks like I've managed to sort it as the cable was faulty
My phone continues to to dhos the moisture detection warning even after it had went away. I have not had any moisture in the phone . I I have kept it in an OtterBox case sent the day I bought it. PleadP let me know how to fix it.
Mine activates for some reason when i leave it charging on the car with usb cable and i shut off the car with the cable still pluged in the phone. I have to take off cable off the phone before turning off the car, if i dont want the warning to come back again.
I had similar issue and I was able to fix it. If you are sure that the surface towards usb c port is not wet, then you can charge the phone. When you charge the phone it will show error message saying disconnect the cable or something. Do not disconnect the cable but restart the phone. Once the phone is restarted the error message will go and the phone will charge normally.
Hope this helps.
Here is a fix.
1. Turn off phone.
2. Partially put charging cable in charging port (about 20% in).
3. Start Phone.
4. When Samsung model number appears push in cable 100%.
5. Phone starts charging.
6. Have a sigh of relief.
Basically put cable in when phone has stared to boot.
for the first time I buy and use samsung product in my life. i bought samsung note 9 in 25th december 2018. after 1 month i used it , I got the same error like you have. no water and liquid touched my note 9 but I got that "mosture has been detected ..." notification. is samsung ready for water sensor ??? samsung note 9 is very expensive but very very dissapointed me. no accurate solution for this problem. to samsung team : if you are not ready for high tech, please don't sell your product with features that you are still not yet knowing and also handling fully. now, my note 9 can not be charged because this notification. I already follow all steps that samsung contact center informed but my note 9 is still not yet charging. please provide solusition for bug on your product.