[sweezyjeezy]

100% o3 has a strong bias towards "write something that looks like a formal argument that appears to answer the question" over writing something sound.

I gave it a bunch of recent, answered MathOverflow questions - graduate level maths queries. Sometimes it would get demonstrably the wrong answer, but it not be easy to see where it had gone wrong (e.g. some mistake in a morass of algebra). A wrong but convincing argument is the last thing you want!