Special Characters in User Names no Longer Work (solved)

Hello!

I created my user name with a "Umlaut" (ö).
Now I cannot log in anymore - the Umlaut appears as a rectangle now.

I cannot even change the name when logged in as an Administrator because I cannot open the profile for that account.
I can search for it using a wildcard with "Find a username", but when I try to open the profile with "Look up user", I get "Sorry, but that user does not exist.".

This must be a recent change.

Edit:
By using Firefox and forcing ICO 8859-1 character set in Firefox I was able to manage the account.