That weakening is “a bearish flag for the strong demand-growth theme” in crude, said Olivier Jakob, an analyst at Petromatrix GmbH based near Zug, Switzerland. “It is one part of the barrel that is not going in the same direction that the flat price is going.”

Link to article: https://www.bloomberg.com/news/articles/2017-11-09/diesel-dip-gives-record-bullish-oil-traders-pause-for-thought