While looking at our PRC gains as a function of time, I noticed that yesterday we had a very abnormal lock.  The lock between approx 01:30-10:00 UTC on 5 Nov 2015 sees a slow drift where we slowly lose power buildup over time, and lose lock when we have lost about 10% of the power buildup.  The IM4 Trans PD doesn't see the power drift, so it's not anything to do with the IMC or anything upstream of that.

All 3 power recycling optics see some drift (as seen by their M3 witness sensors), as do the ETMs (as seen by their oplevs).  This is the same lock that SR3 had its problem where I hand-offloaded pitch from M2 to M1 (aLog 23128), but it doesn't look like that drift lines up with the power drift very well.  Anyhow, I'm not sure what started drifting and why, but it looks like all of these optics' ASC controls are pushing them around to try to fix the drift, perhaps? 

Our locks since this one have been fine, and look totally normal, so I'm not sure that there's a persistent problem that we need to fix, but this seemed worth noting.

The first plot shows the power drift in POP and a Transmission PD, as well as the optic alignments of most of the optics, and the second plot has another few alignment traces, as well as the SR3 cage servo output.