There is a wrong reference in the WPF .NET Core version of Telerik.Windows.Document.Fixed.dll that causes a FileLoadException with the message "Could not load file or assembly 'System.Drawing.Common, Version=5.0.0.0'"
Workaround: Add NuGet reference to System.Drawing.Common, version 5.0.0.0. Note: mark "Include prerelease" so you can see it in the NuGet Package Manager