Windows VMs loose connectivity when moved to 10G bridge

This is driving me nutz. Been troubleshooting this for two days now. I put 10G NICs in my PVE hosts and want to move all networking to them so I can remove my 1G switch. All of my Linux VMs and appliances work just fine as tagged VMs on the 10G vlan aware bridge. The minute I move a Windows VM to the 10G bridge, it loses all network connectivity. EXCEPT it still pulls a DHCP address from the upstream router?.?.? If I move the VM back to the 1G bridge, everything works fine again. Its crazy. The Windows VM will get a DHCP address on the 10G bridge, but then can't ping anything on the same vlan, it's own gateway, or outbound (8.8.8.8). I've verified all switch trunks, vLAN tagging etc.. are configured correctly, adjusted MTU, disabled offload and RSS on the Windows VM virtIO adapters, etc... It's got to be a stupid Windows thing, as all the Linux VMs work fine when I move them to the 10G bridge. Any ideas???