Build fails intermittently due to missing XML documentation files

[BCSharp]

When building locally, I see intermittent build errors like:

C:\Code\ironlang\ironpython3\Build\After.targets(42,5): error MSB3030: Could not copy the file "C:\Code\ironlang\ironpython3\bin\Release\IronPython.Wpf.xml" because it was not found. [C:\Code\ironlang\ironpython3\Src\IronPython.Wpf\IronPython.Wpf.csproj]
C:\Code\ironlang\ironpython3\Build\After.targets(42,5): error MSB3030: Could not copy the file "C:\Code\ironlang\ironpython3\bin\Release\netcoreapp3.1\IronPython.Wpf.xml" because it was not found. [C:\Code\ironlang\ironpython3\Src\IronPython.Wpf\IronPython.Wpf.csproj]

Running the build again sometimes may succeed without errors (and sometimes generate more errors). This can also happen with debug builds. I started getting these errors after the upgrade to .NET 5.0, although it seems more a build timing isuse than a functional issue.

[slozier]

Yes, I've noticed the same. The way I added the .NET 5 Wpf project is a bit hacky so may be worth trying to find a more proper solution.

[slozier]

Seeing this occur again with the addition of .NET 6.