I wouldn't read too much into it -- the same thing happens with pretty much any high-demand/pre-ordered knife that becomes available in one or more large batches instead of trickling out in small numbers. In this case, the last batch of ZT 0551s recently hit the streets, so there were a couple hundred people with new 0551s. Inevitably, some relatively small percentage of those people will decide to sell their new knife for one reason or another (didn't like it as much as expected, funding other knife purchases, flipping to make a few bucks, etc.).