Microsoft number pad outputs several of the same number, only when typed fast.

I'm using a brand new Microsoft Bluetooth Keyboard (this one) on my 2016 MacBook Pro running Monterey. It works fine, except for the number pad.

I was having issues where every time I hit a number it was triggering Num-Lock. I solved that by installing Karabiner-Elements and disabling the Num-Lock key.

The number pad now functions well if I type numbers slowly. However, if I type fast, I get unexpected results... Typing 123 becomes 1213123. 456 becomes 4546456. 50 becomes 5050. 10 becomes 1010 and so on...

I've been unable to find anything on this online and it's driving me crazy. Any help would be much appreciated.