I am because Claude has figured out I am a biochemist and therefore even asking Fable what the weather is gets me bumped back to Opus, sometimes even Opus 4.8 instead of 5. Kimi? GLM 5.3? DeepSeek? No such problem.
I can literally open a new chat with just "Hello" and it gets bumped.
Memories break Fable 5 for me as well in chatbot. I ask Opus a lot of sec related stuff and now if I even type “hello” in chat it gets insta-downgraded to Opus 5.
Claude keeps track of memory if you've turned that on so all conversations are somehow tracked over time Claude randomly will mention that I'm a developer while I'm asking unrelated questions and say oh because you're a developer you might like this or because of my background and infrastructure you might find this interesting and I always get creeped out by it.
They have the concept of incognito chats, but I can see those being worse without context from other conversations happening.
It has figured it out through the software that I work on, data that I analyze, questions I ask, etc. I guess I can't prove it's because I'm a biochemist, but that's the only thing that makes any sense. Either way it won't let me use Fable.
I can literally open a new chat with just "Hello" and it gets bumped.