I've looked at 3 consecutive glitches in TCSX QPD B using the _DQ channels added yesterday.  The shape of all 3 glitches are the same, and have a shape that looks very much like a step function (with a second glitch about 3/4 of the way through the first).  To the best that I can measure in dtt, the interval between the first and second glitch is 900.098 seconds, and between the second and third glitch is 900.577 seconds, so 15 minutes +/-0.5 seconds.  Attached plots of the three glitches show that the ISS and RIN signals also see the glitch.  Related alog 41076.