lmhostid returns "ffffffff" if Hyper-V is enabled. Is this expected behavior?
Yes. Once Hyper-V is enabled on Windows OS, physical NIC will be replaced by software based virtual NICs. Since MAC address of virtual NICs are not proper for HOSTID, lmhostid filters out these MAC addresses, hence returns "ffffffff". For platforms with Hyper-V enabled, HOSTID types other than MAC address should be considered.