This behavior is by design. During an export, the data is written to the VM's disk. If the export is interrupted, the disk is left in an inconsistent state and is of no value.
Exporting across the WAN is not a supported or recommended method to manage Virtual Standby.
AppAssure recommends that, rather than exporting across a WAN, another AppAssure core be set up at the destination site. Initiate replication to to this core and set up the export/virtual standby from the new core. This has the following benefits:
1. An export does not occur until a replication completes, so WAN interruptions will not interfere with the virtual standby.
2. Initial creation of the VM can be faster by preseeding the replica on the target server.
3. Properly configured, an interrupted replication may be resumed at a point near where it was interrupted.
4. Should the virtual standby be deleted for some reason, it can be recreated from local storage rather than exported across the WAN.