Your memories are a function of what actually happened. What you write is a function of what you remember. Two separate processes.

Bias on how you retell your own story is, as you say, a fairly obvious concern, so (for the purposes of this discussion) written autobiographies being biased is completely uninteresting.

Rather, it's the fact that your recollection of events biases towards the positive that's the novel, interesting information.

So you agree there is a correlation and yet you somehow disagree with me. Let's agree to disagree

Yes, there can be but here try to remove the context of writing it altogether. You tend to remember positive memories more than negative memories. That's how our memory works. Period.

Autobiographic memory and an autobiography are two different things