Rising commodity prices have a tendency to push bond prices to go lower while the falling prices of commodities lead to higher bond prices. In other words, most often there is a unique inverse relationship between bonds and commodities. Commodity price trends have been following major bond market turning points for about two years now.
It makes the perfect sense that there should be a lag. Central bankers get used to the fact that it takes 12-18 months for government's monetary policy changes to impact the economy.