(Windows 8.1) Battery stuck at 100% display, even after long usage. Issue persist after calibration attempt.

Recently my laptop battery was busted, and I had it replaced. However, the other day I noticed that the battery display is permanently stuck on 100%.

After unplugging the battery, it does go down to 98%, but a few minutes later instead of decreasing, it pops back to 100%. The laptop was unable to detect the battery draining, and so the "hiebrnate when battery low" function was not triggered. It then shuts off because the battery is drained.

Now when I charge it back up from 0%, it seems to show the battery percentage increasing properly. When I charge it and turn it back on, it shows the battery increasing from 4% all the way back up to 100%. And then it's stuck at 100% again.

I've tried a few calibrating instructions, reinstalled the battery driver, and the same issue still persist. I'm not sure if the issue is with the battery or if it's something with the laptop itself. For all I know the problem is already present before the battery got busted, and I just somehow never noticed (I very rarely pay attention to the battery percentage). Does anyone ever encounter a similar experience and can tell me what I should check?

It's possible that the place I got the battery from had given me a battery that's been deteriorating for sitting around for too long, or because it's a non-original product, so even if it looks new it's already gone bad in the box.