Just an opinion, but maybe low volume + orderly selloff, e.g not hedge fund and quant dumping, but institutional and HNW individuals. Vix usually spikes up when there are high order flows on both sides of the trade.
Yes, that is about the only reason I can come up with myself. All things being equal, VIX should be higher on a Monday, to be down over 200 Dow points and only see 1/2 point VIX rise is downright shocking. But Thanksgiving weekend does need to be priced out at some point this week, today just seemed a little early.