I'm having the same issue.
Not sure if this is what was tried with the clubs, but
My son is on pc and I'm on xbox and we had a similar issue, but S8. It seems to have sorted itself out now though. What we had to do :
We have to set up a new club, I don't remember which of us set up the club.
If you are both in the same club, there is a button in the bottom right of the club tab that says invite all members to party. If you press that it should send an invite, even if showing offline. I don't remember if it was an admin invite or not, but try admin first.
Invite all members was the critical bit.
He appears as a friend now when he's online, but not when he's offline.
Best of luck
Community Manager
