Same here, the thinking square isn’t appearing. I thought I had hit the hidden limit of O1-Pro, but it seems like it’s OpenAI’s issue now…
Quick fix: switch to mobile network
Similar issue at:
https://community.openai.com/t/deep-research-on-pro-account-broken-o1-and-o1-pro-in-web-version-answers-via-o3-mini-while-selecting-o1/1111339