When I switched from “2020 year button” to “2019 year button” it worked. But switching back from 2019 to 2020 didn’t. Rather it raised a 404 error.
Maybe on switching between the buttons, GitHub is sending the request to wrong endpoints.
Strangely works on chrome but not on firefox.
I just wanted to help and therefore putting this here, as the “contact us” form doesn’t have bug/error submission section.