I am using the .NET Upgrade Assistant to upgrade project from .NET Core 3.0 to .NET 8.0.
I am using the in-place project upgrade.

I check the dependencies on and run the upgrade project. At the end I got an error:
Microsoft.Build.Exceptions.InvalidProjectFileException, 場所 Microsoft.VisualStudio.ProjectSystem.ProjectLockService.d__68.MoveNext()...
and in the .csproj file, I see this error:

It turns the BaseOutputPath into 2 lines, and the project should not reload.
Why does this happen? And how can I get rid of it?