I have had 7 total friends accept my Recruit a Friend Campaign invitation, which can be seen in my Mogstation account in the Account Status section. The 5th - 7th friend all accepted the invitation codes during a period where I was logged out. I received the emails for them accepting, but I did not get the in-game message with the gold feather rewards for the 6th and 7th friend joining when I logged in.

My latest message from the Moogle Delivery Service states "A fifth friend has used the campaign code you provided", but there are no messages with rewards for the 6th and 7th friend despite it being tracked properly in my Mogstation account.

Date & Time: July 20
Frequency: 2x

World name: Faerie
Character name: Nia Gamma

Steps:
1. Log out
2. Have multiple people accept Recruit a Friend codes linked to your account
3. Log in
4. Check Moogle Delivery Service