2009Scape Official Forums

When I died I went back to my grave and destroyed it, upon doing so yielded double items on the ground. I could only pick up my original items but the other items showed on the ground and could not be interacted with. Not sure if others could interact with the items though.

From your description, this sounds like a common purely visual issue with 'ghost' items on the ground. There's not really much to be done about it as far as I know, other than that re-logging will cause the nonexistent items to no longer appear.