This is a strange one. Very occasionally, I will be notified that someone has added a PNG file that was generated by the PlantUML macro to a page that contains the same UML diagram. They haven't made any other edits on the page or to the diagram or to any other attachments, nor does the new PNG appear anywhere on the page.
It's almost like an accidental mouse-over and drag-and-drop copied the generated PNG to desktop, then they drag-and-dropped it into the attachments list. But, I doubt that they would have done it on purpose; they probably don't even know how. We're asking one of the users what happened now, but if it was accidental they may not even realize what happened.
Has anyone else seen this happen and do you have any idea what might be occurring? I'm sure it's user error but can't envision what steps would cause this to happen.
Using Confluence server 6.2.3