Alexa, Thomas, Evan
Over the past 24 hours, the alignment slider values of MC1, MC2, and MC3 have been changed. (Perhaps the WFS offloading script was run?) However, these new alignments weren't saved.
This morning, we changed the IMC guardian from LOCKED to DOWN to do a scattering test with the Y arm. When we brought the IMC guardian back to LOCKED, we found that the WFSs would cause MC2 trans to ramp continually in a saw-tooth fashion, from about 100 % nominal transmission to less than 50 % transmission.
Eventually Alexa figured out it was because the guardian had restored the old, previously saved alignments for MC1, MC2, and MC3, and this had caused the beam to fall off WFS A and WFS B. Dialing in the new slider values for MC1, MC2, and MC3 (and then saving them on the IFO ALIGN screen) made the WFS loops work again.