Hello everybody. I bought a Chinese version of mi 10 ultra with Ali. after a couple of days of use, problems with the battery appeared, namely, the battery charge began to drop sharply, then after a minute it rose to 100% and after a while came back to its current state. periodically, such drops in charge led to the disconnection of the phone. also noticed that when fast charging at 120W, the phone's charging mode turns on and off. the mains supply is normal and the cable is not touched. what could be the reason for this problem? the phone has been used for less than a week.