Taking a snapshot on a restored offline VM immediately after Failback or Failover may fail. This error is transient and will self-correct. Wait a period of time then retry taking a snapshot. (DRBC-6824)
Snapshots of protected VMs will fail while their respective DRVA appliance or replication log are down. (DRBC-6529)
Logical consistency-based I/O errors may appear for VMs running on a snapshot. This is a known VMware issue fixed in ESXi 7.0 u3f. For more information refer to: VMware ESXi 7.0 Update 3f Release Notes. (DRBC-6767)
If the DRVA or replication log is not available, vMotion for an affected VM will fail with timeout. It may take several minutes depending on the number of disks involved. Eventually, the VM will become responsive again on the source host. (DRBC-7046)