I was just doing random stuff on my phone and went to click a button near the top right of the screen, and was mildly horrified to see "1%", so I immediately put it into the charger, where the phone promptly started showing "0%" for the next ~30 seconds. The phone never died.
Has this happened to any of you?
It's a bad battery that's causing this issue. You can't calculate for a battery that's out of spec which is why they drop from 30% to 2% in minutes or shutoff when you still show 20% remaining. The voltage sags below the minimum capable for the hardware.
Maybe. If so, it came from the factory this way; it's always done this.
So, now I'm also concerned about Samsung's QC.