My issue with S2

stand said:
Maybe you just didn't pay attention?
I went back to watch the last episode of the first season, and compared it to the manga.

They skipped an arc (7 chapters or so) about the order members being infected by a "vitamin" made by Komui that turned them into zombies.

It sounds serious but it honestly was the most gag/silly type arc in the entire manga and it only added some laughs, and to show that their headquarters end up destroyed.

So that's why in Hallow you see them in their new headquarters.

Basically the only gap you need to fill is that from the last episode of S1 to Hallow's first episode is that they moved headquarters.
And while it doesn't say that some time passed (?) I can assume it did because Lenalee's hair is slightly longer like how she has it in Hallow.

Oh and people not recognizing her because of her hair length is largely BS. The anime changed her hair the same way it was changed in the manga.
From one chapter to the next and poof her hair is a bit longer.

Someone please correct me if i'm wrong with any of this.

(Edit: For what it's worth- I personally don't think DGM is a very coherent manga at times anyway, it's one of those that needs a re-read or two.)