It’s called bloom, and it’s harmless. Chocolate is made of crystals, and most of the time all the cute little crystals line up. Sometimes, when the chocolate is subjected to temperature fluctuations during the engraving process and shipping they can get confused, and then they get out of alignment. But, only once in a while. The good things is, bloom only changes how chocolate looks, not how it tastes. In some cases, like in the dark chocolate, it even makes your message easier to read!