Don’t get me wrong - you *can* call it a CS according to definitions, but equally correctly you can just call the whole thing Sweep.
The purpose of the definition of CS for me is tied up with other attributes - Casting Arc, Stroke Length - neither of which I ever heard being applied to setting up a D loop.
There is no right or wrong on this IMO. If I look at a Double Spey and for example one where we pop line past the rod tip on the upward Sweep, personally I think a better description of the movements is Sweep, Sweep, Casting Stroke and not Sweep/Casting Stroke, Sweep/CS, Casting Stroke.
As another example the Snake Roll, for me that’s a circular Sweep followed by a Casting Stroke and tagging a CS on to the Sweep... well I don’t think of it when I do it, I only think of the Sweep to position the line and form the D, so there was no moment of intent to make a CS.
It’s neither here nor there of course but it’s worth pondering when you are playing with these casts.
I have held a different view - as you know Lee

Cheers, Paul