Error when building System.ValueTuple in .NetStandard 2.0 project

Question

I have a .NetStandard project that uses System.ValueTuple.

It builds fine in visual studio whether or not I include the System.ValueTuple nuget package.

However it fails either way when I build it on team-city with the error:

error CS8137: Cannot define a class or member that utilizes tuples because the compiler required type 'System.Runtime.CompilerServices.TupleElementNamesAttribute' cannot be found. Are you missing a reference?

Teamcity is hosted on an environment with both the latest .Net Core SDK and the latest .NetFramework SDK.

When I change the target framework to .NetCoreApp2.0 it builds fine.

Any ideas as to what could be going on?

For Reference, here is my csproj:

<Project Sdk="Microsoft.NET.Sdk">

<PropertyGroup>
    <TargetFrameworks>netstandard2.0</TargetFrameworks>
    <Version>$(VersionSuffix)</Version>
    <Authors>**********</Authors>
    <Product>**********</Product>
    <Description>**********</Description>
    <PackageTags>**********</PackageTags>
    <GeneratePackageOnBuild>false</GeneratePackageOnBuild>
    <Copyright>**********</Copyright>
    <PackageProjectUrl>http://**********</PackageProjectUrl>
    <PackageLicenseUrl>http://**********</PackageLicenseUrl>
    <PackageIconUrl>http://**********</PackageIconUrl>
</PropertyGroup>

<ItemGroup>
    <PackageReference Include="Google.Protobuf" Version="3.4.1" />
    <PackageReference Include="RabbitMQ.Client" Version="5.0.1" />
</ItemGroup>

<ItemGroup>
  <Folder Include="**********" />
</ItemGroup>

<ItemGroup>
  <ProjectReference Include="..\**********" />
</ItemGroup>

Answer 1

The error went away when I started using DotNet Restore instead of Nuget Restore.

I have no idea why.