I am very curious what either person asked that led them to say that AI had told them a square is not a rectangle.

The obvious question of “is a square a rectangle?” is definitely NOT causing any LLM to say “no”.

Hallucinations are an issue but they genuinely are no longer a concern for any modern non-tiny LLM for basic facts that you would expect a K-6 course to cover. Maybe you might be able to find a few random hallucinations in knowledge covered at the high school level but I’m quite skeptical even that still happens. Yes, they can still, at times, hallucinate sources but I cannot recall the last time I actually saw this happen. I think it was at least a year ago