@ConquistadoR yea there is mistake
@Blackflamesanji pointed out we're shown the bottom of his beak not the top from the angle he comes from
here mid air his beak is distorted
and he's coming for zoro
his lower beak is straight unlike his upper one
and so no wonder why the following result seemed straight.. the angle he came from and hit zoro showed us the bottom of his beak which zoro deflects
besides if you didn't get it yet what i meant by my reply to you saying "when he opens or closes his mouth his beak is bent something along the lines, what i meant by freaking beak was beaks don't work like that.. they are a part of a bird's skull if their beak bends like some semi-cartilage it would make the skull of the bird vulnerable and king would have been KO'ed long ago with concussion.
that pretty logical and i stand true. unless you have evidence or perspective countering mine