curiousGeorge:
I also saw outliers like these, when I ran my script around 2000, 2001 and 2002 timeframe, though I don't have all the results with me right now. One of the curious things I observed during that time was in certain cases it said something like, "we mailed you a card and it was returned by the Postal authorities. Please make sure you update your address....." Million $ question is why would anybody not care about their GC which was returned back, after getting approved????
And, similar to the outlier you have posited, I did find many outliers which had the 990-999 days message against them. I really have no clue as to what the reason may be. And that too for the case you have posited, it beats me!