we have this up and running on Hyper-V Core 2016.
you have to run some powershell commands on the host and then set the NIC on the server to be a destination port then setup a port span on your physical switch between your source and destination, but it appears to be working now
Powershell on Host
$portFeature=Get-VMSystemSwitchExtensionPortFeature -FeatureName "Ethernet Switch Port Security Settings"
# None = 0, Destination = 1, Source = 2
$portFeature.SettingData.MonitorMode=2
Add-VMSwitchExtensionPortFeature-ExternalPort-SwitchName <Virtual Switch Name>-VMSwitchExtensionFeature$portFeature
Add-VMSwitchExtensionPortFeature-ExternalPort-SwitchName <Virtual Switch Name>-VMSwitchExtensionFeature$portFeature