TestFlight users receiving "Invite code has expired" immediately

We are releasing our app through TestFlight and upon adding a group of users, some of them immediately started reporting that they are receiving the following error:


Couldn't redeem TestFlight invitation code "xxxx"

Invite code has expired


They were attempting this within an hour after we added them via TestFlight.


Has anyone else experienced this? What can be done to avoid the issue?

TestFlight users receiving "Invite code has expired" immediately
 
 
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