Difference being that Predators don't bleed acid for blood, nor have nature body
Didn't stop her from killing aliens with wristblades.
Predator's are consistently taken down in close quarters and with physical impacts.
She blocked and dodged predator punches and threw it around in War. She grabbed the predator's arm and threw the whole predator away, how much does a predator weight again? More than she could ever make it move I'm sure. Not even Dutch could do the things she is doing, and the difference between Dutch and Machiko in streng is not as big as the difference between Dutch and a Predator. It's like having a teenager girl fighting Dutch and not only being able to keep up but throwing a 200+ pounds man around. It's laughable. Dutch's punch just stunned the predator for a brief moment, and Machiko almost knocked the predator out. The predator was being hurt by her kicks.

Big log on the noggin,
That would have killed any human, and he was still alive.
stabbed with a edged weapon, 2 decapitations in Predators - one by a human - stabbed in the chest in AvP.
By non-human weapons that could also cut an alien apart. Pussyface was injured, weak and tired, Classic was killed by another predator, Berserk was caught off guard after being shot with a sniper and Royce hitted it several times, Chopper and Scar were stabbed by aliens. Not the same thing at all.
This character in particular is shown to be skilled
Its not just about skill, she would need super human streng to do what she did, and this is not dragon ball.
and physically capable in previous issues
Previous issues also had those issues.
it's not like there's no precedence for Predator's to have their heads cut off
Yeah... I might get a little off topic here, but decapitating someone is not that easy, not with just one clean strike specially with a being with a thicker skin and bone like a predator. Samurai used to train a lot to get it done in one blow and they still failed sometimes, its a combination of streng, speed and not having the target in motion. Samurai only did that feat in executions with someone unimobile for a reason: because it's not easy to do that in fight (Royce did with a Berserk on it's knees). And that is with a sharp samurai blade, if it's a random knife or even a machete, it will take several strikes to completely take the head completely off, and that's with human skin. Most men don't have either the streng, speed and skill to do it with one strike.

To do what she did here, she would need to be stronger and faster than any human that ever lived.
or be killed in close combat.
Context matters, in the movies the predators were injured + caught off guard, they were never so overpowered by someone, specially someone with a even bigger difference in streng.
Even if it's science fiction, there's still elements of fiction involved.
So it seems.