There is a lot of sarcasm out there on the internet. since GPT-3 was trained on a web crawl its likely it would spit out a lot of seeming nonesense, though its just trying to mimic our flippancy and random humour. Even the AI dungeon finetuning likely had a disproportionate amount of sarcasm and more concerningly really wacky and seemingly impossible events in an attempt by the human dungeons masters at creating humour and excitement, leading to a lot of unpredictability and wackiness that the model has learnt to mimic. I think it doesnt get enough credit when it comes to this, and what often seems like a stupid mistake it made that is funny to us in its stupidity is an actual attempt at the kind of humour a human DM/GM would attempt. Of course I think theres a lot of accidental stupidity, but for some of the exmaples here its hard to tell which is which, and its probably even harder to figure out because they likely most often blend together as sort of half jokes a lot of the time imo