UK Anyone else had this experience?

Has anyone else noticed that on the expiry date on the back of their bag of Oxbow Cavy Cuisine pellets it's a sticker with a date on, but under the sticker is another 'expired' date. I asked my vet about it, whom I bought it from, since their supplier had sent out of date stuff before. They didn't know, but phoned either the supplier or Oxbow, and sent the bag back because the supplier/Oxbow had no idea why my bag was like that. Then they came back saying that it was fine, that it was normal, gave me a new bag with same sticker arrangement, and apparently it was a mistype? It looks and smells fresh and new, just wondering if anyone else has one of these double dated bags?