Days ago a costumer reported that saw duplicated MACs in all hosts of a Hyper-V Failover cluster.
And Powershell showed that was true, in both teamings (Look on VM and MGMT) in every host we saw duplicated MAC.
The solution was force MAC Address in both teamings with a new MAC.
To do that, I went to Device Manager and I added 90-E2-BA-7B-DD-A7 and 98-BE-94-2B-92-C6 for my case in that host (Of course on the others Hyper-V hosts I did the same but with different MACs).
Remark that Hyper-V and SCVMM use different MAC Address scopes and doesn’t overlap.