Humidity seems to worsen this moisture warning problem on my phone, here in SW Florida humidity is extreme. I flatened the end of a tooth pick to make it soft like a brush, moistened that with 90% isopropyl alcohol, used that to clean lent and debris from charging port, blasted port with canned air (dust off) and no more moisture error . It might be necessary to clean the connector on the cable as well. Last resort might be a wireless charger, that also worked for me. Good luck!
I haven't the noteworthy ultra and it is doing the same thing here in NC. I haven't cleaned it and put it in a bag of rice to soak up the moisture. I never had any problems out of any my my other galaxys like I am having with this one. And the only way I am able to charge my phone is wireless and it is super slow. The bad thing is my phone allowed me to charge it with the cord last night and when I took it off the charger the moisture notification came on and has been on all day. I am at my wit's end atm and am running out of ideas atm
its weird im having the same exact issues. A certain charger will make it go "moisture detected" even tho phone is dry n wire is dry. Which is not the oem wire. But with the oem wire i rarely get super fast charge like you said i have to flip the wire and connect it upside down to get it to fast super charge. And its not always working either. Usb disconnects sometimes aswell its a brand new phone.
My S20+ is only charging wirelessly (slowly) since yesterday. No spills/drops and only slightly humid conditions. The Moisture warning and alerts if plugged continue since I first saw this yesterday morning. Already been a huge headache. Samsung is directing me to an ubreakifixit place to look into warranty issues.
Samsung, please help!