1pw extension doesn't fill in credentials at eisbedarf24.de

Having an account at onlineshop http://www.eisbedarf24.de 1password doesn't fill in the credentials.

Not from the extra menu when one clicks on the account icon in upper right, not from in the page https://www.eisbedarf24.de/Mein-Konto when you click in the password or username ("E-Mail-Adresse" field.

BUT if I click on the button of the browser extension's symbol beside the address bar and choose Autofillin it DOES work. Also, it does NOT work if I click the extension's symbol in the username or password field. 

Tried with latest Chrome, Firefox, Safari, Edge on MacOS 15.5 (M1 MB Pro)