Major character who has only appeared on 1 page in the entire OOTS saga

[Emanick]

He's also in a one panel update about why the comic was late.

Yeah, in bed with a greenish skin tone with his wife bringing him soup, if I recall.

(Not sure if that's still accessible to us, I'm going from memory and it's likely been 10+ years since the last time this bit of Burlew work was used. Also likely doesn't count as part of the official story + prequels, anyway.)

I think you two are describing two separate one-panel strips, which appear side-by-side at the very bottom of this page.

I don't know. I'm not saying I think it happened... but... if it did, it wouldn't be all that extraordinary. Look at all the plotholes we find in movies, which are overall pretty short works reviewed by countless people. They obviously also slip a lot into books, given these are longer works managed by fewer people. This comic? Is enormous volume of content, managed by a single person.

Not every artist is an accountant at heart, keeping detailed spreadsheets of every single character and events.

An accidental plot hole and the truth or falsity of a very specific promise aren't really comparable. The former merely means that the creators haven't thought through every possible implication of a given scenario; the latter means that a creator specifically chose to say something that was verifiably true or false. You could argue that The Giant simply forgot about an extra appearance, and didn't bother to double check, but I find that hard to believe, since the book with the quote we're referencing also has a shout-out to the specific thread that makes checking the veracity of his statement trivial.