Mortgage rates are based primarily on the price of mortgage-backed securities (MBS), which are essentially bonds consisting of numerous similar mortgages.  MBS have experienced their fair share of volatility over the past two days, but all of it has taken place in a narrow enough range that mortgage lenders haven't been forced to make big changes.

The average conventional, conforming 30yr fixed rate is right in line with the same levels seen on Friday.

Bond market volatility is increasingly at risk of spilling over and affecting mortgage rates in the coming days.  This is especially true next week as markets digest the newest Fed policy announcement next Wednesday, but Thursday's policy announcement from the European Central Bank could also cause enough of a stir to impact U.S. rates.  

Even without these looming policy announcements, rates are simply more likely to make bigger moves after a period of consolidation and decreased volatility.