iphone says it's charging but it isn't
iPhone 12 mini. Battery capacity 98%. Problem was with 15.x and now with 16. Connected to Apple mag safe charger, over night, phone not in use. I put it on the charger and it goes thunk ding and the green circle goes around. Battery setting screen shows it's charging as does battery icon on home page, which means the phone is connected to a live line. But the phone discharges. See screen shot below. Under normal circumstances the phone doesn't lose this much charge when not being used. Considering how much it's discharging it seems as though something is drawing power, so it isn't just idle. This doesn't happen every time, though. Help please.
iPhone 12 mini