It fails to extract from the DLL with Error 193, which suggests that it's a bitness mismatch. So, I replace the x86 files in the nuget package directory with the x64 files, straight copy and replace, and re-run the build process, no other changes. It works, and correctly gathers the registry information. I'm thinking this is either an undocumented misconfiguration on my part, or a bug.
Describe the behavior you expected and how it differed from the actual behavior.
I would expect to be able to Harvest the DLL and for it to correctly generate the Class/Registry entries.