I recentered the beam on WFS_A of IMC because the beam was found to be off from the diode by a couple of mm horizontally. Probably I accidentally bumped a steering mirror when I was working on the GigE cameras on IOT2L. And indeed, no other photodiodes showed such a big off-centering. Due to this WFS_A without the beam on its diode, IMC ASC kept unlocking IMC. After the centering, IMC ASC came back to normal. IMC seems stable.

Also, I noticed that the whitening gain for both WFS_A and B was set at 45 dB which should be 36 dB according to this alog (alog 9094). So I set them back to 36 dB.