My phone charged from 0 to 56% in couple of minutes?

Yesterday my brand new TCL 10 Plus ran out battery so I plugged it in. I went to get myself some water and when I came back I saw that my phone somehow charged itself up to 56 percent! In minutes! I used it with that charge and it used 25 percent in 25 minutes then turned off at 20 percent. I factory reset it and everything seems OK for now. Could you guys tell me why would something like this happen?

Welcome to Android Central! Are you using the charger that came with the phone?

Sounds like a bad battery, which can happen on new phones. If still under warranty, it may be covered.

Classic bad battery symptoms, with the speed of the charge, drain, and shutdown you reported. I'd definitely be requesting a replacement.