@hege Late reply on this topic, but relevant.
Hyper-V SR-IOV implementation does NOT support mac spoofing with SR-IOV
Technical;
Mac spoofing is required for CARP because the mac address is changed on outbound packets, that's part of CARP.
Hyper-V natively does not allow outbound packets through the virtual switch from a Hyper-V guest that does not have the exact same mac address as assigned to the virtual machine (unless you enable the "allow mac spoofing" checkbox.
SR-IOV technically can allow mac spoofing, this is all there in the IEEE specification for for this is to work, but, quite simply Microsoft Hyper-V doesn't implement it.
Therefore you need to enable "allow mac spoofing" and forego SR-IOV or VMQ network accelerate functions.