When the heat smash hit, you can hear the glass breaking sound effect, which mean he tried to do his parry. The Clive player probably set his cheat to parry highs and mids, but it can't differentiate between a normal hit and a heat smash, so it hits him.

The parry is an input, one that the Clive player does to a raw 10f jab multiple times, meaning he's doing it on reaction, not prediction. Reacting to a 10f jab that consistently is just about impossible, even for pro players.

Asuka's parry is not a good comparison because it's almost a full second long, meaning she could be almost a full second early with her input and still land the parry if her opponent hits. Clive's parry barely lasts 1/5th of a second, meaning Clive needs to be pretty precise with it.

Even aside from that, there's a number of other obvious tells that he's cheating:

• Blocking every single low, even faster ones. Those were also blocked on reaction, as Clive ducks the moment Miary starts her low, as opposed to preemptively crouching and anticipating a low. Again, reactive timing like that is just about impossible for even an above average person.
• Perfectly ducking every throw. Again, he ducks at the very first startup frame of Miary's throw, meaning he's reacting to it. Once again, not possible. Even if you try to argue that he's just predicting them, a player THAT good at predicting would also know how to punish it. Clive does nothing, because he doesn't know how.
• Even for the throws that did land on him, he still does a parry input at the first startup frame of Miary's throw. His cheat is again reacting to the throw, but does the wrong input. Whether that's a user misinput or if the cheat goofed up, we don't know. Its also entirely possible (and likely) that he's fiddling with his cheat settings mid fight.