I think you're going to find that Pergo will immediately deny your Warranty Claim. The dropping of a glass of water may be considered an 'every day spill' and it won't be a problem is you 'remove the spill promptly', but those can be subjectively interpreted.
Here's a copy of their warranty. Just be sure you read the one that YOU have. As you will see, there are a few of them. Pergo Warranty
You will find that Pergo will tell you that you didn't use enough glue when you put the floor together. They'll tell you that the only way water can get THROUGH the 'top layer' is if there's no glue or not enough glue where seams are put together. Hence, the water swells the plank. I suggest you hire a professional to do the repair/replacement of the bad plank(s). Hopefully, he'll warranty HIS work.
I've yet to hear from someone that's ever successfully made a claim with Pergo. (I'd like to know the details too as to how it was done.) IMO, and you didn't ask for my opinion, is that this type of flooring should not be used in kitchens, laundry rooms, bathrooms, or in basements/rooms where the floor has 'moisture issues'. Personally, I can't stand the stuff! Some people have great success w/it. These folks tend to have it in their living rooms, dining rooms, and family rooms, and/or bedrooms, and these rooms are usually ABOVE a heated and dry room (below).