Depends heavily on the area. I've seen a bunch of bots correcting nonsensical "textbook" issues in languages like Java. The more common the topic among new learners, the more random PRs you get. But apparently even projects like linux kernel aren't safe https://github.com/torvalds/linux/pulls?q=is%3Apr+is%3Aclose... (for context, this repo doesn't accept PRs as development happens in mailing lists)