21.12.12.2 causes internal clr errors

[pardeike]

I am having issues with the latest MMC 21.12.12.2
I got a lot of Azure failures so I ran Release mode tests on my local machine and go internal clr errors in .NET 5 (among others).

How to reproduce
Check out master on Harmony where I reverted 21.12.12.2 back to 21.10.10.1 and verify that all tests pass.
Now update /Directory.Build.props so it uses 21.12.12.2 and run all tests again.

/Andreas