ZB futures are priced at $0 on 12/22/2016. This is really problematic as buy and hold on any sort of leverage with these contracts will generate a margin call, even if you're not trading on this day. It needs to be fixed. The price never dipped to $0 at all on 12/22/2016 in charts. 

ZB22H17 Sell Market
Fill: -$0.0078125 USD

-1 Filled