Cannot add value less than 1

I'm currently on 2.0.4 using PHP 7.4, and I have a weird bug. When creating a bill, I cannot add a value less than 1. I'm trying to add 21.05, and after clicking save, the value comes out as 2,105.00.

I have no clue why this is happening. It works like this whether I set the tax or not.

Ok, I figured it out, I think.
If anyone else is having this problem, just try to change your punctuation regarding thousands and decimal points in the currency settings.
For some reason, the thousands separator was "." and the decimal point was ","
I switched those, so that they are in the correct English GB order (thousands separator , and decimal point .) and that fixed the error.