New Class instance not picking up enforced workflow

You should be able to add the workflow and state as simple propertyvalues just like the other properties in you example. That way you won't have rely on the automatic workflow settings.

If I recall correctly the workflow setting in the class is only a directive for the M-Files client, it does not add or enforce the workflow on the server side. So if you are creating objects via the API, you need to set the workflow and state yourself to the built-in properties (ID 38 and 39).

This.

The data is used by M-Files clients but is not enforced by the server.  Either ensure that you read the data (it can be read from the object class data via the API if you don't want to hard-code it) and provide the workflow and state properties when creating the object, or use a server-side event handler to react when the object is created and explicitly set the workflow if it's missing.