In many cases like this it's requirements from the prompt that are leaking trough. It's usually stuff that matters for the model itself writing the text/code, but are irrelevant to the end user and add noise
Yeah I find that when adding a feature they’ll often add irrelevant stuff to the documentation, stuff that mattered during the conversation like “we removed feature X” - which was only added in the current commit and was never actually deployed, or “feature Y does not support use case Z” which is just something I told it, nobody is going to be interested in what this thing doesn’t do. The most recent models seem a bit better at this I find.