Magic Keyboard draining batteries suddenly

I saw that a few people had this question before, however I did not find any kind of helpful solution to this issue. Sorry if this is repetitive.

My Magic Keyboard is draining batteries in hours. Before, I could use rechargeable batteries with both the mouse and the keyboard and recharge them every few weeks (as I don't use my computer much). Usually, I'd have to charge the mouse batteries more often as the keyboard went on for a couple of weeks more. However, as of late, I noticed my keyboard was eating batteries really quickly. At first I thought I had to get newer batteries because maybe their performance wasn't at its best, but that didn't change anything.

Today, I was working with keyboard at 5% battery and my mouse at 80%. It lasted around 20 minutes. When the keyboard shut down, I got an old mouse with no batteries needed and used the batteries for the keyboard. They went from 80% on the mouse to 16% on the keyboard in a matter of 10 seconds. I got the notification of low battery INSTANTLY.

Is this normal? Is this an issue regarding my own keyboard or a generalised problem?