Previously, ChatGPT redirected the Pro model series to GPT-mini (based) model (seems to be using for internal CoT formatting).

Mine was displayed as gpt-5-mini, but now it seems to be using gpt-5.5 mini, verified from colleague.

How to check if you have been affected:

1. Ask GPT Pro, "What model is this?"

2. GPT Pro mostly thinks for more than 5 seconds, so in most cases, it doesn't think too quickly.

Please share your experiences if you have encountered the same problem as i would like to check: 1. Ask GPT Pro, What model are you? 2. Export your datas: Settings -> Data Controls -> Export Data 3. Check exported data has string like i-cot or gpt-5-5-mini.

In my case, I was unable to use Pro model for a few days, but the problem was resolved after I changed my email address from Outlook.

It was the worst experience, spending $200 for researching purpose.

I have been contacting the customer support ticket since May, but I have not received a proper response, and my ticket was automatically closed. I also contacted them on Twitter1 a few weeks ago, but received no reply, leading me to suspect that they are doing this intentionally (due to like abusive users).

Example is like: https://chatgpt.com/share/6a603bf3-0590-83ee-9f56-6d8b573d43da

Thanks.