The smoke has a hitbox. Can we get a visual confirmation on that?
You are the first person to mention a smoke hitbox. There were a few comments about the "un-z-cancelled" hitbox being some kind of ground aerial. All of this is wrong, just absolutely wrong, sorry! :D The fact that it makes sense is irrelevant, except at explaining the tenacity of unreasonable beliefs.
What is happening with the Kirbs Neutral Air is that the hitbox is simply still out, either the front or the back one, which due to the geography of that move combined with low damage quick recovery of say a Jiggs or a Yoshi makes the second (double hit) much more common.
At risk of being shouted down:
A hitbox must connect with a hurtbox for a hit. Two hitboxes can interact in a variety of ways and I am unaware of any aerial versus ground rule, what is that assumption based off of?
A quick look at
http://FrameDisplay.SuperSmashBros64.com can show that the Kirbs Forward Air and the Falcon Down Tilt have ample room for the hitboxes to interact, harmlessly, without a hurtbox being involved. "Clank" is sloppy terminology because it then defines these things as needing the damage differential to happen, when in reality two hitboxes can interact easily without regard to what either of them is. This is why priority doesn`t exist, also, another chink in the move versus move analysis falling short.
To be as simple as possible:
If a hitbox does not hit a hurtbox, you will not get a hit.
This is most assuredly what happened to Solo, and without anyone needing to have a memory/observational lapse for it to make sense.
Please object to this with facts so I don`t regret posting it. Thanks! Have a nice day!
Edit: For better demonstration, and fun, try to land hits on Samus charge shot that produce this effect, like a non-fast falling Kirbs down air isn`t so hard to rig.