You absolutely can see repeat mentions from the same post. Depending on who set up sending them, they’re not necessarily idempotent. Certain systems, if a post is edited someway, will not only resend but have different identifiers. That could also explain the # discrepancy. One can be the amount of inbound and showing anything that’s inbound. The other may have Manton attempting to process to not have a repeat webmention seem new.