The same issue exists in Ubuntu 14.04, Evolution 3.10.4 with the Hungarian keyboard layout, where You have to press AltGr + V to get the @ character. If any character is already present in any of the address fields then after pressing AltGr to type the @ immediately a ', ' appears, similarly to clicking back and forth with the mouse between the fields. I.e. some kind of next address autocomplete function is triggered.
The same issue exists in Ubuntu 14.04, Evolution 3.10.4 with the Hungarian keyboard layout, where You have to press AltGr + V to get the @ character. If any character is already present in any of the address fields then after pressing AltGr to type the @ immediately a ', ' appears, similarly to clicking back and forth with the mouse between the fields. I.e. some kind of next address autocomplete function is triggered.