Zero'd the Match gains starting at 1549utc.  Jim reports the X leg of the sensor dropped by ~1/2 on 23 Dec when it appears the zero button was pressed.  We will press it again to see if that might bring it back.  I can't find a log of a button press but we had been struggling to get that STS2 signal down to reasonable levels.  We're not sure this will work but we'll see.