New Redmi 9t MIUI 14.0.3 Battery Draining and Shutdown Issues

[GuntherFromPH]

I have been using this redmi brand for three years now, no miui updates we're shown after 14.0.3. Yesterday it drained so fast and shut down in 20%, I leave it for charging until 100% without even touching it, then unplugged it and went to bed. I woke up and checked it and saw it in 91% without even using it. In this very time that before I am writing this, it got shut down at 39% and later at 36% showing a battery that it's empty, I charged it again and it came back hopping from 36% to being stuck at 30%. What makes this issue and how do I fix it, is this a bug?

 

[JiaiJ]

I don't think you are using this custom ROM (so it does not really make sense as a bug here), but an hypothesis would be that your battery requires a replacement.