I'm not sure when it disappeared, but I can't update my service references anymore, this is all new, I updated them like a month ago in a previous VS version without problems...
It's in a solution with a Xamarin Android project, the service references are in a .netstandard 2.1 project.
Also, if I try to add it manually from the Service References manager, weird errors pop up, and they don't make sense since using dotnet-svcutil is working:
We are experiencing this same problem in Visual Studio 2019 (16.11)
It is apparently fixed in an upcoming release. https://developercommunity.visualstudio.com/t/16110-update-service-reference-missing/1500425
This situation is common when I add references, delete references, and then re-add services with the same name. The type conflict seems to be caused by an old file that remains in a place where Visual Studio can still see it. All you need to do is clean it up before adding a new reference.
1.Delete the service reference in question.
2.Click the project name in the Solution Explorer to highlight the project.
3.Right-click the project reference.
4.Near the top of the context list, click Cleanup Items.
5.Add your service reference as usual.
Here is a similar example：https://github.com/dotnet/wcf/issues/3827
