The kids are more of less going crazy from being couped up. First John hating Con Air, now we have Rose actually made an alcoholic drink. Dave may or may not be going crazy due to drawing KARKAT ON A PENIS RIDING INTO THE PENIS SUNSET WHILE LORD ENGLISH IS LOOKING OVER. They may be immortal, but they are still human. Sidenote, I think that the Gamzee we saw is still the old Gamzee, and that the Gamzee that Jane had unfortunately faced is one in the future. I guess I found it a little confusing as to why this Gamzee is acting all crazy when we saw the Cod Tier one; after all this time, that little piece of information clicked in me.
Spoiler
Or maybe they are just growing up? They are 2 years older.
Even more off topic, I'm very sure Damara is now THE memetic molestor of Homestuck. Well yes it's pretty much obvious she's got a really dirty mind, but the real question is if she's just all words or not.