nuget build warnings are not treated as errors

[mtfriesen]

Nuget warnings are not causing our builds to fail, i.e., are not being treated as errors:

Build succeeded.

       "D:\xdp\xdp.sln" (Clean;Build target) (1) ->
       "D:\xdp\src\nuget\nuget.vcxproj" (default target) (25:2) ->
       (PostBuildEvent target) ->
         EXEC : warning : NU5129: - At least one .props file was found in 'build/native/', but 'build/native/Microsoft.
       XDP-for-Windows.Sdk.props' was not. [D:\xdp\src\nuget\nuget.vcxproj]

    1 Warning(s)
    0 Error(s)

I've tried adding -Properties TreatWarningsAsErrors=true to the nuget pack command, but this did not work.

Edit: it works if you hit save...