Workitem Not Deleted

[Tara Wilbanks]

I have a situation where a workitem has been completed, as indicated in
the workflow log, but the workitem is not deleted from the user's inbox.
The inbox has been refreshed but the workitem is still there.  At this
point, it has been several hours since the workitem was completed but it
remains in the user's inbox.  The user has even logged off and back on and
the workitem is still there.  Any ideas why this would be?  We are on
4.6C.  FYI .... When I list the user's workitems to be processed using
SWI5, the workitem is not there.
 
Thanks for your help,
Tara