Traders are seeing a big red flag for oil

Crude oil has fallen about 12% from the most recent peak reached two weeks ago. 
Oil prices fell hard after OPEC failed to reach any agreement on production limits, and again postponed any decisive action to its next meeting. 
But that's not the biggest red flag for the market, and where prices may be headed next, according to Credit Suisse's Jan Stuart and his team.
What's more troubling, they wrote in a note Wednesday, is that the gap between prices for contracts to deliver oil