Security Issue? Highly Unusual Post

On my forum, I recently noticed an out-of-place post. It was spam posted in a locked section by someone with no username. The posting date was 2013, but it definitely wasn't there a year ago. The join date of the non-user is 1969-12-31. It was linked in a widget on my custom homepage, too. I have removed the homepage widget, but I kept the post on the forum in case any Forumotion workers needed to view the post itself.

Hello @TMV

It could be down to this problem
https://help.forumotion.com/t153651-important-back-up-of-all-the-deleted-messages-and-topics

I don't think you have anything to worry about just go ahead and delete it.