Accessing Task properties via reflection only works if the properties are explicitly accessed in my code

I'm trying to access a property of a Task in an MS Project via System.Type.GetProperty("Finish"), but it looks like the property (and others like it e.g. Number1) is not accessible via reflection unless my code specifically uses that property. Is this a compiler setting that I can change? I'm writing a synchronization engine so it is impossible to tell ahead of time what field of a Task the client system may request.

So with the example below info will be null.

System.Type ty = typeof(Task);
System.Reflection.PropertyInfo info = ty.GetProperty("Finish");

but with the code below info is returned as a valid PropertyInfo object.

Task tk = activeProject.ProjectSummaryTask;
object done = tk.Finish;
System.Type ty = typeof(Task);
System.Reflection.PropertyInfo info = ty.GetProperty("Finish");

I basically expected GetProperty() to work for all the properties listed in the API for Task (which are quite a few).

Here is a link to the API for the Finish property: https://docs.microsoft.com/en-us/dotnet/api/microsoft.office.interop.msproject.task.finish?view=office-project-server