We're suddenly seeing issues where 1 or 2 machines in our company can't compile code, whilst our pipeline and everyone else can.

Are you missing an assembly reference?

They appear to be due to .NET Core's Transitive References, because the errors are correctly flagging for projects which do not directly reference their dependencies, but happen to get them from some other reference (which is why it works on everyone elses machines).

What we can't understand is why this is only happening on some. There must be some local machine configuration somewhere which configures whether to allow Transitive References or not? (everyone is building with the same code, Visual Studio, and MSBuild version).