We have seen the same problem with missing fiducials.  Our supplier is 
     using horizontal hot air leveling equipment.  The fiducials were being 
     'ripped' off by a roller at the exit of the machine.  Like your 
     problem, the missing fiducials were isolated and, naturally, at the 
     same location on every board.  Our supplier changed panelization of 
     the board and added some thieving circles around the fiducials to 
     prevent future occurrences.
     
     Regards,
     Jamie Baumgart
     DSC Communications Corporation
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