It's possible that while your team members have taken the test, they may not have yet accepted your invitation to join the specific team. To ensure they appear in the group, remind them to accept the team invitation you sent. For further guidance on inviting teammates, you can refer to this article.
Please double-check you are sending them a group invitation and an individual invitation. To learn the difference between the two, check this article.
The easiest solution to fix this solution is to copy the invitation link for the group and share it with your team members directly.