Bug: MSBuild doesn't build all variants

[applejag]

Expected behavior

Building with MSBuild either via dotnet build, MSBuild.exe, or via Visual Studio 2019 results in all the different DLLs used in the package:

/bin/Debug/unity-aot/Newtonsoft.Json.dll
/bin/Debug/unity-standalone/Newtonsoft.Json.dll
/bin/Debug/unity-editor/Newtonsoft.Json.dll
/bin/Debug/unity-portable/Newtonsoft.Json.dll
/bin/Debug/unity-tests/Newtonsoft.Json.dll

Actual behavior

Only some build. Sometimes it even takes multiple builds to get the most builds. But never the full list.

The missing build DLLs are:

/bin/Debug/unity-aot/Newtonsoft.Json.dll
/bin/Debug/unity-standalone/Newtonsoft.Json.dll

Steps to reproduce

• Clone repo
• Open solution /Src/Newtonsoft.Json.sln in Visual Studio 2019
• Start build Ctrl+B

Details

Host machine OS running Unity Editor 👉 Windows

Unity build target 👉 N/A

Newtonsoft.Json-for-Unity package version 👉 12.0.301

I was using Unity version 👉 N/A

Checklist

• [x] ~~Shutdown Unity, deleted the /Library folder, opened project again in Unity, and problem still remains.~~ (irrelevant)
• [x] Checked to be using latest version of the package.