I experienced the moisture indicator problem on my customer's Note 10 Plus. She was positive that it had not been exposed to moisture. I tried all of the non-invasive methods mentioned in previous posts, with no benefit. Through process of elimination, I concluded that there was a failure of the moisture sensor on the charging port board. So I replaced it, making sure to perfectly match the model number on the board with that of the phone. (This is extremely important as a slight mismatch will result in the device going into a semi-airplane mode.) Problem resolved. In this instance the issue was physical, not a defect in Samsung's programming or software.