http 421 - misdirected request in Safari 12

Dear community,

after upgrading to IOS 12 I can't login in my web banking anymore. The server just responds with http status 421 'misdirected request'. After analyzing the network calls I recognized that this happend on a redirections from the login page to the actual web banking page. However if i manually copy the delivered location address and follow it, I can Access the page.

I checked this behaviour with several browers (including Safari 11) and all of them were able to follow the link even if they get the 421 status. does something has changed in Safari 12 which messes up the redirection?

Thanks