We noticed that at least three times tonight, DIFF lost lock because of glitches in the ALS (Y) refl control signals.  The times were 0:18:12 UTC, 1:35:00 UTC, and 1:47:29 UTC, we didn't investigate all of the DIFF lock losses we had tonight so there could have been other examples.  The glitches were both more frequent and larger in the Y arm, but there are also glitches present in the X arm (they are independent glitches in the 2 arms).  We see the glitches even without ALS DIFF and COMM locked, they aren't in the optical levers, the PZT signals, or a number of other things we looked at.  

Evan and I drove down the to Y end to look on a fast scope at the glitches.  By the time we got down there, the glitches had largely stopped.