In the SDDC Manager, when the Update tab is selected from a Workload Domain, the following entries can be found in the LCM logs:
YYYY-MM-DDTHH:MM:SS:sss+0000 ERROR [vcf_lcm,ccac############,669c] [c.v.v.l.r.a.c.v.u.UpgradeAssemblers,http-nio-127.0.0.1-7400-exec-3] Failed to load NSX-T Cluster with id <Cluster ID>
and
YYYY-MM-DDTHH:MM:SS:sss+0000 WARN [vcf_lcm,#######################,eef2] [c.v.e.s.l.a.i.i.InventoryClientImpl,http-nio-127.0.0.1-7400-exec-1] NSX cluster <Cluster ID> does not exist in auditedNsxtClusterMap
These entries appear for NSX-T clusters that were previously removed from the environment.
SDDC Manager 5.X
This happens because the upgrade spec still contains the NSXT ID in the history and it is printing it in the logs.
The log entries are from the log trace and can be ignored. This does not have any impact on upgrade or day-n operations.