Here is a table of the most recent 30W (or similar) locklosses, and what we could find so far:

1228172266   25W
                       This was a radiation pressure compensation instability that hit us even after going back down to 25W from 30W. We believe Hang's new gain table (alog 45750) should prevent that now.
1228198761   30W
                       POP_LF starts dropping away 2 seconds before lock-loss (and REFL_LF starts rising)
                       OMC length locking loop shows an oscillation for the last 15 seconds
                       REFL_RIN sees a burst every ~8sec (microseism). All LSC signals also show significant microseism motion.
                       This lock has the boost10W filters in the ASC HARD loops off.
1228201480   30W
                       PRC2Y has a large excursion. Not clear whether it is a runaway.
                       13Hz oscillation visible in SCRL/MICH/PRCL/REFL RIN in REFL_RIN it looks like a sawtooth
1228203545   30W
                       ASC looks perfectly fine. 
                       POP90 increases 2 seconds before lockloss. POP18 start dropping at the same time.
1228205888   28W
                       ASC looks perfectly fine. 
1228247359   30W
                       0.5-ish Hz ring-up in ASC: CHARD_Y, CSOFT_P/Y

Given that a number of them seem to suggest a fast CARM loop problem, we also looked at the CM and IMC boards. Note that during POWER-UP we lower the gain at the IMC board output (MCL gain and FAST gain), so the signals through the board increase. However, we looked at the read-backs - all signals are less than 1V. But we should still check for high-frequency saturations.