This occurs in the following workflows:
1. Scheduled task Delete Snapshots with Retention days via vSphere client under Virtual Machine > Configure > Scheduled Tasks
2. Delete All snapshots with the retention days for the VMs which are hosted on ESXi versions earlier than 8.0.3 from vSphere client.
ESXi versions lower than 8.0 Update 3
vCenter server version 8.0 Update 3 and later
This is resolved in vCenter 8.0 U3e (P05) and will be resolved in a future release of 9.x
References:
How do I Schedule Tasks for Snapshot Deletion
Upgrading the vCenter server solely to vCenter 8.0 U3e (P05) is insufficient; the ESXi host must also be patched to version 8.0 U3 or newer to resolve the issue.