Recently there have been a few people who have accidentally reported visitor messages sent to them by others. In the section for giving a reason for reporting the visitor message to the staff, they just put in what looks to be a reply. In other words, people are mistaking the "report" button for a "reply" button.
I have made a nice little picture that will hopefully explain how to reply to a visitor message clearly for those who may have some confusion.
I hope this helps! :)