I've been told many times that for ERS Day 2 to work I need to add the user into the Day 1 and Day 2 groups in the source tenant.
After Discovery runs, these group memberships are replicated to the target tenant.
Why does the user need to be in both groups for Day 2? Is it a group replication thing, or the way the product is coded?
If I add someone into only the ERS Day 2 group in the source tenant, will ERS still actually work or will it fail?