November 30, 2020-KB4586876 Cumulative Update Preview for .NET Framework 3.5 and 4.8 for Windows 10, version 2004, Windows Server, version 2004, Windows 10, version 20H2, and Windows Server, version 20H2 Failed Windows Subsystem for Linux Succeeded November 10, 2020-KB4580419 Cumulative Update Preview for .NET Framework Succeeded
After failing all the time, these worked February 9, 2021-KB4601050 Cumulative Update for .NET Framework 3.5 and 4.8 for Windows 10 Mar KB4023057: Update for Windows 10 Update Service components And then this failed every day May 11, 2021—KB5003173 (OS Builds 19041.985 and 19042.985)