I thought it was pretty common? Pre-LLMs I've always opened PRs to self-review before asking anyone to review it (sometimes leaving myself comments), now I'm also having an agent review it and leaving its own comments that I might answer, seems like a very normal thing to do.

I do ensure these self-conversations are resolved so that the PR is clean when I ask other reviewers to have a look, and I don't think I'd do that on an open-source project. But I'm very much shrugging at this practice.