When you attempt to export a virtual machine with delta disks (mostly with VM snapshots) under vSAN ESA datastore as an OVF using ovftool on the guest OS environment, only a part of the data data on the entire diskChain will be copied to the vmdk of the destination OVF, resulting in the data being broken on the vmdk of the OVF (cannot be used normally).
Perform remove_all_snapshot operation and disk consolidation operation (to make sure there won't be any delta disks) on the source VM before exporting the OVF