I have ZCS 5.0.15 network installed on two different server both Ubuntu 8.0.4
I selected Italian for the interface and it worked well, then I switched to English United States and on one server I see some labels in english and other in italian for example
Contatti instead of Contacts
Preferenze instead of Preferences
And in keyboard shortcut everything is in italian

I tried to restart zimbra, to empty the browser cache, but the problem still
I checked cos, account, domain and global configuration of both servers
and I didn't noticed any difference.

What can I check ?

Thank you very much