Whenever I use o3-mini or o1 (not the preview version), I receive responses with messed-up styling. The first and second screenshots show this issue for o3-mini in different chats. The third screenshot is an example of the correct styling I got with Claude.

The API doesn’t seem to be the problem, as it looks fine in another app I tried (4th screenshot).

I haven’t tested all the other models, but among the variations of Gemini, Claude, and other OpenAI models, only these two have this issue.