Windows Server 2012 R2 Hyper-V and Windows Failover Clustering are enhanced to better detect network connectivity issues for virtual machines. If the physical network assigned to the virtual machine suffers a failure (such as a faulty switch port or network adapter, or a disconnected network cable), the Windows Failover Cluster will move the virtual machine to another node in the cluster to restore network connectivity.
This is for ANY networks attached to the VM, not just those used by clustering.? So if there is an attached network that you wish to be monitored for failure, ensure the option is enabled within the settings for that VM.
In Windows PowerShell the Set-VMNetworkAdapter cmdlet has a new parameter to control this feature, -NotMonitoredInCluster.