Have you tried using other distros on your WSL? If they are also unable to connect, it would be a WSL issue, especially your WSL Virtual Adapter, which it will be a better idea to report at GitHub microsoft/WSL repository; If they can, this would be a Ubuntu problem, and I will investigate further. Right now I am still unable the reproduce the behavior on my three machines using Windows 10 20H2, Windows 10 Beta Channel, and Windows 10 Dev Channel.
Have you tried using other distros on your WSL? If they are also unable to connect, it would be a WSL issue, especially your WSL Virtual Adapter, which it will be a better idea to report at GitHub microsoft/WSL repository; If they can, this would be a Ubuntu problem, and I will investigate further. Right now I am still unable the reproduce the behavior on my three machines using Windows 10 20H2, Windows 10 Beta Channel, and Windows 10 Dev Channel.