I thought the same, and I haven't looked into this too much so I can't say for certain, but it sounds / seems like the guys behind this version of Segwit2x (which again, really isn't S2X) set up futures on the 19th (which so happens to be when prices spiked). I don't bother with those futures though and they usually aren't that useful. Just interesting to look at, but tend to overinflate prices.