Yes that is exactly what's happening.

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.

Im starting to doubt you actually used fable