Language Switch at Front Page

It's my first post here. I hope it is the right forum thread.

I installed i18n, path modul and global redirect modul and set for language negotiation: domain name only.
All works fine. Only the front page is an exception. If i switch the languages the domain changes but the standard language remains.

But this only affects anonymous user. Very strange...

Did someone experience something similiar? I hope for some suggestions. Thank you very much.