Posted: 08/09/2013 at 20:27
Hand-timed races are prone to this sort of error, especially if the finishline gets busy. If a few runners cross the line very close together then the time recording team and the bib-number recording team can get out of step.
Having compiled hand-timed results myself I know it happens easily enough. I almost relied on people pointing out the errors, so that I eventually got it about right.