The bug was described here: 3F/DllExport#56
For example, the following definition below should cause a problem as for #1:
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>netcoreapp2.0</TargetFramework>
</PropertyGroup>
</Project>
The default XML namespace of the project must be the MSBuild XML namespace or no namespace.
The bug was described here: 3F/DllExport#56
For example, the following definition below should cause a problem as for #1: