Symptoms:
VMware vRealize Operations Manager 6.x
VMware vRealize Operations Manager 7.x
VMware vRealize Operations Manager 8.x
VMware Aria Operations 8.x
This issue occurs because upgrading or reinstalling a vCenter Server cause duplicate objects in VMware Aria Operations as all objects under the vCenter Server have a new UUID associated to them. These duplicate objects do not have the historical data of the original objects.