Battery Icon glitch

I think my iPhone XR is experiencing an icon glitch for the battery. I installed iOS 14 I think a few days or a week after it came out, or possibly even the day of release, and only recently is my battery icon having issues. The maximum capacity for the iPhone’s actual battery is 89%, which I know is good, so it shouldn’t be that. The problem I have is once I reach 99%, the icon won’t show 100%. Only after restarting my phone does it show 100%. In fact whenever I’m done charging it, the icon goes down 1-3%, and it stays at the percentage it last went down to. Restarting it seems to show the correct percentage, as it goes up 4% or how much it went down by, and doesn’t seem to do that again when restarting it. This only happens when I’m done charging my phone. So does anyone know what might be the problem, and if so, how to fix it?