Am I doing something wrong?

Yes, but not in the code snippet you've provided.

How do I troubleshoot this to determine if the javascript side of the code functions properly (which my logic is saying it is not)?

Take the project I've provided below, where you code works , make changes to how you have it configured and then save it back to a Github repo.

Did the above problem come about because I moved the code to a separate Class Library and now there is a conflict in some code? or could it be related to the fact that Visual Studio was recently update? - should anyone know.

Maybe, but unless we can see more code then don't know.

Here a working version of your code: https://github.com/ShaunCurtis/SO79568191

Note the settings in App - <Routes @rendermode="InteractiveWebAssembly" />.

On automating sequence numbering, this question and answer provides information on why you shouldn't do it and links to further documents on the subject. https://stackoverflow.com/a/78952688/13065781