I feel like https://xkcd.com/221/ might be heavily influencing what the typical "random" die roll looks like on the internet ;)

Based on this comic I've seen unit tests use 4 as replacement for random generated number to ensure non flakiness (of course, only when needed). But it might explain the LLM's bias?

Haha, I didn't know that one! It's consistent with OpenAI's conception of a "random" dice roll :-D. Joke appart, I'm quite convinced many people would not find 1 or 6 to look "random" enough to be chosen as an example dice roll.