An extra temporary file (named [filename]_preripped.pdf) might be generated when the Pre-Rip options are used in an Expose or Proof ticket.
Symptoms
If the original file has an external reference that requires pre-ripping, and you enforce pre-ripping in the Expose or Proof ticket by enabling Resolve Transparency and/or Convert Strokes, then a temporary file (called [filename]_preripped.pdf) is created next to the original job, instead of under a (hidden) tmpgrs subfolder.