Population Migration / Travel
After waves of ships, the last wave of traveling fleets heading to the Alpha Avior System wind up missing, their ships simply gone while they passed through the Surro Aster Cluster.
Out of the thousands of ships, almost 1/8th of the later waves do not make it to their destination near the planet of Diadem, where they would be either left in stasis or put to work on one of the four new planets. This cuts into plans of revival and reproduction, leaving the leaderships in charge silently panicking while keeping the information secret.