Alliance management: "External Forum" & "External Homepage" not working

So when I try to save a link in "External Forum" or "External Homepage" on my alliance's profile, it doesn't work.

I copy-paste or manually type the link in the appropriate field, then click "Save settings", and I receive the message "Settings saved". But when I quit the page and come back, the link is gone. If I change other settings, they do get properly saved.

Can someone help me out?