Depends on the author. Some people don't post to arXiv until after they've submitted, or after they've gotten initial reviews back. Others like to post to arXiv

Depends on the author. Some people don't post to arXiv until after they've submitted, or after they've gotten initial reviews back. Others like to post to arXiv proactively to get feedback prior to submitting. Just depends on the person. Reviewers are encouraged not to read anything that might be such a paper, though, for whatever that's worth.