Cursor not in first input field of login form

[sjvudp]

URL

https://www.openstreetmap.org/login?referer=%2F#map=6/51.330/10.453

How to reproduce the issue?

Originally described in German: https://community.openstreetmap.org/t/cursor-im-login-formular-in-das-erste-eingabefeld-positionieren-was-spricht-dagegen/112560

When opening the login form in Firefox, no cursor is visible; specifically it's not visible in the first input field.
So typing goes to "somewhere", but not to the first (username) input field. When using KeePass auto-type, the password might be pasted into the username field.

Happens in Edge also, BTW.

Examining the login form, the first input field is a hidden one. Maybe the simplest solution is to place the input field after the "real" ones. Also it's debatable whether a hidden input field should get the focus (and invisible cursor) if it's the first one.

Screenshot(s) or anything else?