Xamarin - Multi-targetting - "'System.ValueTuple`2' is declared in multiple referenced"

It might've been added automatically as a reference from another package. Just remove that NuGet package to resolve the conflict.

uninstall-package System.ValueTuple is the command for the package manager console.

I don't which assemblies the conflict occurred in. However, I realized I had not myself added the ValueTuple nuget package so I explicitly did and the error went away.