Looking more into the MC, it appears that no spot centering was done after the power attenuation optics were removed (see elog 8142). Since Manasa had changed the zig-zag steering after putting in the attenuation optics (elog 7843) the pointing was not correct for the nominal MC. This is (likely) why Yuta and Manasa found some significant decentering. If Manasa's tweaks when preparing for vent were primarily in yaw, then this is most definitely what happened. A note, this is why we should change to inserting the attenuation optics before the PMC, but even so, one should adjust the angle of the PBS, NOT the zig zag optics, to get the input pointing back to the same place. This is also why it is useful to ensure the attenuation optics do not block the PSL pointing QPD pickoff, so it is easier to adjust the PBS to get back to the original pointing.
In any case, I touched the last zig-zag mirror in yaw today (the top of the knob was moved away from me) to recenter the spots.
With the MC unlocked, I centered the WFS. Now the MC is back to its normal working condition....WFS are on, autolocker is on, reflected DC power is low, etc., etc.