We've been getting reports of folks having this trouble. Sorry my friend. The only solution is checking to make sure there's no moisture or debris near the charging port. Updating the device to the latest software is the next step. If the issue does continue, we'd need you to make contact with LG for more help. Sounds like you're getting another device, so you've done what you've needed to do to resolve this.
I messaged about this issue several months ago. I updated, cleaned the port, did every recommended process, same issue. There had not been any moisture. There seems to be skepticism about this, but I don't understand how, if there had been unknown moisture exposure, the phone still be working well with wireless charging several months later, and the port still be wet. LG and Tmobile were both non-responsive except for sympathy from TMobile. This is baffling because if you look online for 30 seconds it becomes quite clear this is an LG 6 software problem. And their not addressing the problem means I will never buy another LG product. Wireless charging is challenging - hard to do on the go or while traveling, and slow. I will have to replace the phone before it is paid off this summer before traveling. I got on this forum today to see if there were any updates but the messaging is just the same. So disappointing. Guess I should be glad TMobile has been a good carrier in so many other ways, but I sure wish SOMEONE would own this problem instead of just putting it back on the consumer.
I'm disturbed by T-Mobiles lack of assistance to these folks with the moisture message. I've been getting the same message and I just moved my phone to a different charger and it's charging fine with no message. Hmmm Could the problem be in the charger and not in the phone?
Never had any moisture near my phone but I just had crop up.
I cleaned the port, plugged it back in and the same message appeared, even after turning it off while trying to charge it.
I tried another cable on the same LG charger and it began charging. Whew!
I believe what we are seeing here is a message that should be reworded to reflect the possibility that a cable might have a short in it or possible moisture.
The batteries have something similar to GFI circuitry to protect it from being shorted out which is why this message is popping up.
I take it all back. Now it's doing the same thing with the second cable and I even tried another charger.
Two threads worth checking out regarding this issue.