I added 3 users as Internal testers in Users and Roles > TestFlight Beta Testers.
In My Apps > Prerelease > Internal Testers only 2 of them appear.
The missing tester is an Admin/Legal user. They haven't received the TestFlight email invitation.
Are iTunes Connect admins Testflight internal testers by default? If not, did I miss any step in the process of getting them invited + added + receiving new builds in the Testflight app?