As a part of several suggestions to address the clipping on IM4 trans and the ISS QPD, Keita suggested I check the POP QPDs to see if things have changed there since the vent. Here are two ndscopes comparing the PIT, YAW and NSUM channels of both POP A and POP B QPDs. The two screenshots show the last lock in January and the recent lock yesterday. It appears that the overall power on the QPDs is about the same, but the alignment on POP B in particular has changed significantly in pitch, close to -1 and probably to falling off.

We servo on POP A during DRMI lock, but do not use POP B for any control (to my knowledge).