For Business | Why can't new members see assignments?

Question:

Is it possible to add new team members to existing assignments

Answer: 

Currently, new members cannot be added to existing assignments. If a new member joins a group after the administrator has created an assignment, that member cannot see it.

As a workaround, the group admin can create a new assignment for everyone or individually assign a new assignment to the new member(s). Note that assignments do not require members to re-take completed content, so members who have already completed the assignment will automatically be marked as complete.