It kills me to say this, but you are really only safe if you refeed the decks. The problem was with an uninitialized value, so the actual behavior is predicated on the order the cards were fed (ie, unpredictable). Also for the record, it is 64 card ids in a CC session, not a deck.
I am actually quite surprised it doesn't go bang the instant the 65th card id gets fed. I suppose if you had no overvotes in a 500 card deck you could feel pretty safe, but with even one overvote you could never be absolutely sure, and even then a blank race could have turned into a voted race.
For all I know the odds of your decks being incorrect may in fact be low. It sounds like this could be the case else you would see the overvote symptom more prominently. The problem is that you could never be sure even with one overvote.
Maybe too much information...