Bonds began the day roughly unchanged and rallied modestly until 9am ET. There's been steady selling since then. 10yr yields are now up 1.8bps at 4.597 and MBS are down 2 ticks (.06) in 5.5 coupons. This is 5 ticks (.16) below the AM highs, which could coincide with some earlier lenders' rate sheet print times.
As such, the earliest, jumpiest lenders could be close to considering negative reprices.