I believe that the dates added on some bottles are when the bases (flavors, VG/PG %s) are mixed. However, some places then add the nicotine when you order it. I would call/email and ask what that date refers to.
The vendor I bought this from is a reseller. I would assume that it was prepackaged when they got it.
Well, not every batch comes out the same I guess. I highly doubt Litecigusa is short sheeting a customer, as they are outstanding. Could be anything from a topper, your taste buds, etc. Good thing its only 15ml and not 50ml.