Hello, @marzio.biancardi@gmail.com,
Yes, our theme is fully compatible with the WPML plugin, this seems to be the WPML plugin setting issue, Could you please once reach out to the WPML support here: https://wpml.org/forums/forum/english-support/ and ask for help on this issue, I am sure they will help you in this case.
Regards 8Themes Team.