This is more of a heads-up than a dire reprice alert. MBS are still up 1 tick on the day (0.03) and things have been reasonably flat all day. Slow erosion in bonds has now added up to MBS being down just over an eighth of a point from the mid-morning highs. Since those highs coincide with some lenders' rate sheet print times, negative reprices can't be ruled out among the jumpier lenders.
Best way to use this alert: as a cue to lock if you were already planning on locking today (no point in waiting for a positive reprice now).