ChatGPT has been silently routing Pro to mini for several months

(disclaimer: author)

ChatGPT has been silently downgrading pro model to mini model for several months. I have relevant evidence at the http request/response level. OpenAI ignores.

This issue involves redirecting to mini that is 40 times cheaper than Pro, when GPT 5.4. I feel like Anthropic moving Fable requests into Haiku without user's consent.

I have more stories but I don't have health&motivation, I'm stopping to write at this for now.