While attempting to create a BattleSquad, I encountered a problem when trying to invite someone:
I had a message about trying to invite someone whose name was also taken on another server and told to add @servername when inviting:
Which I did: I tried @jiangdu and @eu1 but in both cases I was told that the character doesn't exist or as deleted.
The character in question was able to invite just fine so the battlesquad could be created in the end.
However when he tried to invite to a group, it popped up as nickname Unknown sending the invite.
I've tried to invite him with Unknown just now in a new battlesquad but it doesn't work either.