Same issue with a generation 2 VM, Ubuntu 20.04.3, Hyper-V 2016, linux-azure kernel in use. Does not happen with our generation 1 VMs. Same workarounds of unselecting VLAN ID checkbox and/or setting the NIC to 'Not connected' works for us as well.
Same issue with a generation 2 VM, Ubuntu 20.04.3, Hyper-V 2016, linux-azure kernel in use. Does not happen with our generation 1 VMs. Same workarounds of unselecting VLAN ID checkbox and/or setting the NIC to 'Not connected' works for us as well.