I’m tested on 23w18a, can confirm.
It’s mean 1.20.x-1.21.x both exist this bug.
It’s has a temporary resolution:
Find your own language translation file, copy it to other dir and rename this file to en_us.json, then create a resource pack to include this file, finally drop this resource pack in “Resource Pack” interface and enable it. It’s will show your own language.
Here is the example resource pack: (It’s Simplified Chinese language)
It’s effect 26.3-pre-3 and 26.3-rc-1.
Now, the “Edit Game Rules…“ button is not enabled or disabled until you enable or disable commands, apply changes, then return to the same menu again.