One of the points from the CSPO class I attended, last year, that stood out to me more than anything else, was when the instructor told us that one of the roles of the CSM is to coach the CSPO and make sure the CSPO is fulfilling his or her role.
That statement, by itself, was not a cause for concern. The concern came from realizing that there were things taught in the CSPO class that were not taught in the CSM class. My question to the instructor was, "How can the CSM coach the CSPO on things the CSM is not taught?"
I don't have a satisfactory answer, but over the past several months as a ScrumMaster/Agile Coach, I've come to realize that the Product Owner is the most important role on the team, and I'm coming to appreciate the challenge created when the Product Owners are also Product Managers.
Is there a difference between Product Owners and Product Managers? Your company might not treat them like there is, but I'm learning that there is enough difference in the roles that it is difficult when one person is expected to do both, when both are required.
The simplest way to put it is that the Product Manager is externally focused, getting funding for product development and working closely with customers, while the Product Owner has an internal focus, creating user stories and supporting the development team. Yes, there is much more to both, and some overlap, but the Product Owner role is different from the traditional Product Manager role.
When I attempt to look at this situation as a ScrumMaster, I have to wonder, does this mean that I am also expected to understand the Product Manager role?
I'm not ready to tackle that question, right now. However your organization is organized, make sure that your Product Owner/Product Manager is empowered to make product decisions. How effective would sprint planning or backlog review be if your Product Owner had to take a list of questions back to someone else to get answers or approval to changes? It doesn’t matter if you have separate a Product Owner and Product Manager, or one person filling both roles, as long as the person filling the Product Owner role has the authority to make decisions for the project. If your Product Owner is also a Product Manager, recognize that it is a big job and be supportive. If the Product Owner fails, the project fails.