This update is effectively a cancellation of the previous alert. Liquidity issues have been resolved for now. UMBS 4.0 coupon prices moved up a quarter of a point in a few short seconds. They're now up 3 ticks (.09) on the day as opposed to being down an eighth of a point moments ago.
This is no guarantee that illiquidity will remain at bay going forward, but it lowers the risk of negative reprices for now.
10yr yields are unchanged since the last alert--still down 6bps on the day at 2.78%.