I’m convinced all of the major LLM providers silently quantize their models. The absolute worst was Google’s transition from Gemini 2.5 Pro 3-25 checkpoint to the May checkpoint, but I’ve noticed this effect with Claude and GPT over the years too.

I couldn’t imagine relying on any closed models for a business because of this highly dishonest and deceptive practice.

You can be clever with language also. You can say “we never intentionally degrade model performance” and then claim you had no idea a quant would make perf worse because it was meant to make it better (faster).