I would not stress about the label on this nonconformance. It looks like one of those majors that you can close remotely. Look into the format that you are using to capture your Management Review Records and make sure that as input requirements are called out. If you you don't have one, certainly I recommend that you create a template for it.
To start off, what impact is having this NC, is delaying certificate, will this affect your organization? Time to solve it?; the standard is clear about, what is a major.
If major, does not affect you in some way, solve it right away, if it does, you can talk with your CB, and convince him about the NC category, could be minor, additionally it can be solved quickly, while major, for sure, requires a full deep analysis and time.