As of moments ago, the problem persists as described.
I called Turbo Tax support yesterday. It was a 2-hour call. We concluded that my PC is not a horcrux. Instead, the issue is likely a communication issue at the Turbo Tax server side. The Turbo Tax specialist found where this issue has been referred to the developers for investigation and resolution. The reference number is INV-20910. I was told to give it 2-3 days. We shall see.
