Ah! I have an old version of the project to try it out on and I see what you mean. It's not obvious from the Navigation Pane that that Namespace exists but changing it as you say does do the global update.
So scratch any mention above of it being a problem/bug 🙂
On a different subject: do you know of a way of changing the behaviour of the Class Properties node to NOT show the full namespace hierarchy? It tends to be wiiiiiiiide, adjusting any container (e.g. a case node) automatically. I always have to shrink it back down to the width of the property(-ies) I use and makes that title bar of no use.