From time to time there is a duplicated post appear (1.jpg). When I choose to delete 1 of them, both of them are deleted (2.jpg). When I press button "show deleted post", it appears there is only 1 post that was deleted (3.jpg). Then I press "undelete" and the post is restored (4.jpg) and the duplicated post is gone. Is this issue connected to Xenforo itself or is it an improper behavior of [WMTech] Double Post Merge plugin?