Nicovideo requires that you make an account, to view videos.
Even though only the second hit of Dizzy's 6H is JCable, you are allowed to JC it as long as the first hit made contact. What's happening is:
You hit Ky with the first hit
The second hit whiffs Ky, but still hits the bubble.
Then you are JCing the second hit.
For anyone else that wants to see this. Select Dizzy for yourself, and Ky for the dummy. Set dummy to no guard. TK a Punch Bubble, land, then 6H~8.
You can also see yourself JCing the second hit of 6H, without it hitting, by doing the same thing but omit the Bubble.