I noticed that the X arm green PDH was not able to keep up with the longitudinal motion today. It kept unlocking every 5-10 seconds. I  am not sure if this is due to high wind today. The roof wind monitors read 20 mph on average and reached 40+ mph at highest in this after noon.

I switched the ISI-ETMX stage 1 back to low blend, 45 mHz in X direction (which is exactly opposite of what Sheila's instruction says in alog 16583) without the BRS correction. This apparently helped the PDH locking as it became able to stay locked.