The [OES] diagram can be seen as a “window” of your model, it only shows the model elements and relationships. Model elements and relationships are not captured in one diagram, but in the model file.
A diagram is the Capella tool mechanism to visualise a view.
The Capella tool does have two files: .aird and .melodymodeller. The first stores the model and Arcadia model elements relationships, the second stores the Capella diagram representations.
To answer your question, if you change a relationship and create a new relationship to a different model element in your cloned diagram, it will be replicated in any other diagram that is shown.
Thank you very much for your reply and for the link to the document.
It makes sense that diagrams are just views into the model - I describe this to my colleagues like an individual image of a CT scan of a head or body, or other 3D object.
I have not yet fully internalized all of Arcadia’s and Capella’s concepts and how they relate. That will take a bit of time