https://s3.mangadex.org/data/37701a5226a998c7a4f9bdfbfdffb0c1/x6.png
"Woah" is not a word. However, "whoa" is a word. The letter 'h' is the second letter, not the last.
Just turning on a spell-checker would prevent this. Even a simple web browser spell-checker. For instance, I'm using Chrome and its spell-checker easily catches the mistake.
I'm not singling this group out, since I see many others making this same mistake all the time. But it's so easy to avoid this error that there's really no excuse.
https://www.slate.com/articles/life/the_good_word/2013/12/whoa_or_woah_correct_spelling_and_variants_of_the_increasingly_popular_word.html
And yes, you may have seen me make this comment elsewhere. At this point, I'm basically making it into a copy-pasta, since every manga group seems to copy the incorrect spelling off of each other.