Characters Are Able to Get Hit for No Damage?

Using Kingdom Hearts II (I don't think there are any attacks that are knock-back and send characters flying in the first game), if a character gets hit with a knock-back attack, a second, consecutive attack will show as having hit them, but no damage will be received.

Skip to 22:54 here and watch until 23:07. Pay close attention to Donald's HP and MP meter and notice how his hit points go down when he gets hit, but then when he gets "hit" again, it shakes and flashes light red (because it does that when characters are hit), hit points do not go down:

Thoughts? What do you think, @iwantedtoexplode?

 

After taking a close look at the part of the video you mentioned, I noticed that Donald flinched and slid back a bit when he took the hit that lowered his HP, but on the "hit" that seemingly did nothing, he didn't flinch at all and acted as if nothing happened yet his HP/MP bar still shook. If I had to guess, I'd say it's either a glitch or perhaps Donald had some invincibility frames from the previous hit that were still in effect, but he still came into contact with the hitbox of Pete's shockwave attack, thus causing his HP/MP bar to shake with no loss of HP.

Of course I could be dead wrong on the invincibility frames thing. I haven't played KH2 in a long time and the mechanics of that game haven't stuck with me, but that's what it looked like to me.

 

It's probably the latter if it happens to all characters, including Sora / Roxas.

 

KH2 has some weird invisibility frames, a great example is the first Xemnas fight, the blades get recognized as a hit, and the laser effects appear on Sora but he doesn't flinch or take damage.
Also, do you spend your free time watching that same Pete boss fight

 

It's one of my favorite battles.

 

@HeartlessOfLight, @hatok

Doing some researching, it seems that the invincibility frames, if they exist, only take effect when the character hits the ground. Either that or it depends on the attack.

See here in my first walkthrough of Kingdom Hearts II how Donald kept getting hit by Demyx's attack, really bringing his health down: 29:16 - 29:32

 

I know this was already answered pretty much, but, @HeartlessOfLight and @hatok, if you guys are interested, there's a much better view from 5:35 to 5:41 here:

Past Pete knocked Sora into the air and present Pete's bowling bomb did no damage when Sora landed back on the ground, but it caused Sora's HP and MP meter to shake.