No sense in overcomplicating or overexplaining... Absent the Fed, MBS trading levels are easier for a smaller number of traders to push around. Today's 30yr UMBS settlement (April coupons delivered) could also be adding to chunky trading.
Either way, prices have almost fully recovered the previous losses. 2.5 UMBS are 6 ticks (.19) higher on the day at 103.98. 10yr Treasury yields are down 9 bps at .66%.