Resource Assignments Disappeared Without Explanation, But Units Remain

One of our schedulers has been working in our Server Based Primavera P6 EPPM environment, using version 23 and has had something happen we have not been able to trace the cause of…

Their schedule had basic resources assigned to the appropriate activities to establish the initial histogram for our key trades' FTE hours. After a couple updates, the scheduler went to look at/share the updated histograms and all the resource assignments had disappeared, however, when you added the Units columns to the schedule table, the baseline/actual/remaining units are still showing up as if they resources were still assigned. Since there were no assignments, the histograms were at zero.