Can we actually have a CIVIL discussion instead of telling people to fuck off in every other post? :wassat:
If so, let me throw in my two cents.
No, I don't think the chapter was mistranslated. However, like many professional translation, liberties were taken.
It's a necessity in translation to prioritize the flow of the language, and thus take liberties in translating content.
I myself have done professional translation for video games, and am fully aware of this.
However, there are times when I feel certain liberties seem rather… unnecessary.
Let me use this chapter for example.

molo translates this scene as:
Marco: We'll protect him at all costs, just like we did Ace!
This is of course, a correct translation. For the first bubble.
The entire content of Marco's second bubble has been omitted.
The line in the second bubble reads:
Marco: If we let him die… consider it a shame to the Whitebeard Pirates (pride)!
Now, even after considering liberties taken by the translator, I don't see why it was necessary to omit the entire bubble?
If this was not a decision by molo, perhaps he missed the bubble, or the editor/scanlator missed his translation quote?
Another case that seemed arguable was the choice of "Dark Dog" for 冥狗.
Yes, 冥 can mean "dark". It also refers to afterlife, hades, and is synonymous with hell.
So "Dark Dog" is defnitely a possibility.
However, the concept of hellhounds already exist in myth and popular culture.
I find it natural for the meaning to be refering to hellhounds, especially considering the concept is quite common in Japanese. (commonly addressed as 地獄の番犬)
I'll also add, that the image many Japanese manga readers associate 冥 with is commonly that of hell, afterlife, and hades, especially when used in context of a fantasy coined word.
I admit, I haven't read many scanlations of One Piece around, since it's obviously not a necessity for me. 
However, from what I have read here, I do find CNet's translations to be more in tune with One Piece fandom, and more accurately carries over the feel of the original script.
molo's script feels very professional and clean.
However, precisely because of that, it also has the same complaints I feel towards many professional translations, be it Japanese to English or English to Japanese, which often is directly related to how familiar the translator is with the subject.
(Oh god, don't get me STARTED on professional Japanese subtitles. LotR film localizations were absolutely terrible! And coming from a respected film translator too.)
Ok, after all this rant, let me close my statement saying....
well, it's still just an underground unofficial (and illegal
) fan translation of a comic book. It's no big deal.