Our setup is the following:
Three Dell Poweredge R720s running Windows Server 2012 R2 (which was upgraded in place from 2012). These servers run Hyper-V and we use Virtual Switch Manager to manage the networking in the VMs. Due to the fact that the Ethernet ports do not map to the correctly labelled Ethernet adapters in the operating system, we have notes in the Hyper-V switch manager to show which virtual adapter is mapped to which physical port.
I'm not sure if it was after the upgrade to 2012 R2 or something else, but the notes from the Virtual Switch Manager have just disappeared. Everything else has stayed the same, but there's no notes any more. Has anyone else encountered this? Is there any way we can prevent this happening? We believe it is also happening when we do live migrations, but we need to do a few more tests to see what happen when, so I can't confirm.