Yes.
The narration is constrained to successfully inform players of the changed fiction in order to - crucially - inform what they think, say or do next.
This can be on the cubes side only, though. There's no need for an arrow from cubes to clouds to pass information to players. You can have a cubes to cubes interaction do this, and, crucially, 5e is full of these things. So are other systems, in different places (or the same places, depending)!
The chosen words vary by group, but the litmus test is the same. Do players have information that rightly influences what they say next?
Look at the DW hack and slash canonical example.
Where the goblin counterattacks? I mean, you put this up against a 5e attack, where a successful hit in 5e reduces hp on the goblin (same) and then is done (not same)? Here, the attack did damage, but also generated a cubes to cloud arrow in that the goblin counterattacks!
A better example for you would be choosing the other option for the 10+ Hack and Slash, where the player is making the choice on the cubes side to prevent any cubes to clouds arrows being generated that are unfavorable to the player. The attack could, at this point, roll minimum damage and not kill a goblin, and so, yes, here the result in DW would remain on the cubes side.
So you only care about the F if it has a G consequence, rather than a next-F consequence?
The exact opposite.
I'm 100% familiar with it. It says "narrate the outcome." Since it's not written in terms of this model, it doesn't make clear that narration is a fictional thing. I can easily narrate, "okay, goblin takes 4 damage, still there. Turn done? Okay, Bob you're up." You're asserting that this is in error, and against how the game tells you to play. Okay, even going with this, then what we have is that the GM's narration is inconsequential. The GM narrates that the goblin is reeling, but this cannot be leveraged for any future actions at all -- there's no available action declaration that can take advantage of the goblin reeling.
As player, I can. My next hit might down it? Right, I bonus action flurry instead of patient defense. Fiction changes.
This isn't a fictional thing, though. Declaring a flurry is a cubes thing. You don't have to engage any fiction to flurry, you just announce it. You "press the button" and it happens.
This also doesn't take any fictional advantage from the goblin being described as "reeling." You could have been told that the goblin has 2 hp left and make the same decision.
When you think it's not about fiction changes, you've misunderstood RPG.
I haven't, at all. We're not at a high level. We're in the weeds. We're looking at a specific loop of play and analyzing how it interacts. It's ridiculous to insist that every moment of an RPG be about the fiction. It cannot be -- there has to be some mechanism to resolve disputes at a bare minimum (I'd also argue for more minimums, but this is sufficient for the current point). And that mechanism cannot be part of the fiction because we, in the real world, are using it to determine who gets the say. It could be cards, dice, roshambo, coin flips, asking Bob to say, whatever. We can also build systems that stack these non-fictional elements -- like how a successful attack roll leads directly into a damage roll and that leads directly into applying damage to hp totals and then if hp total is reduced to zero is an arrow to cloud
mandated. That mandate is important, because it's identifying when a system is telling you that an arrow must be generated. You can add other arrows whenever, but they'll be arbitrary and quite possibly of no impact.
Here's an example to play with. Your 5e PC is facing a goblin. You just performed an attack and the goblin is described as "reeling from your blow." What can you do with this fiction? You have no other information, here -- you do not know how much damage you did, or how many hitpoints a goblin might have or how many it has left. You're a complete neophyte. The goblin is reeling, what does this allow you do to in the fiction that you could not do before?