I've tried to port a .Net Framework library to .Net standard 2.0.
This library makes use of the ONVIF web service. The WSDL files can be found here : https://www.onvif.org/profiles/specifications/

In Visual Studio 15.7.6, when i try to add a reference to "https://www.onvif.org/ver10/events/wsdl/event.wsdl", this error occurs :

Error : An item with the same key has already been added. Key: CreatePullPoint

So, i've tried to use the Dotnet svcutil tool 1.0.2,
dotnet svcutil https://www.onvif.org/ver10/events/wsdl/event.wsdl, but the same error occured.

What's going on?