"If you've two Hyper-V failover clusters managed by SCVMM2008 R2, it's possible that you can't complete a LAN migration of a Virtual Machine from one of the clusters to other. This issue will only appear if ALL of the following conditions are met: VM is created using Hyper-V (i.e. the VM wasn't created through VMM Administrator Console); VM is made into an HA VM using the FOC GUI (resource name will be called something like "Virtual Machine <vmname>"); VM is in a running state; VM is migrated to a different cluster. VMM will chose QSM (Quick Storage Migration) network migration (LAN migration) in this case," explained Microsoft in KB2417319.
When the migration fails you'll see following error: