We started having trouble handing off in DRMI_TO_POP.

- The symptom is a ~10000ct offset in H1:LSC-POP_A_RF9_I_NORM_MON just before hand-off.
- We checked all the phasing of POP9 and REFL 9,27,135 - they all look reasonable.

- However the whole thing seems to be related to a CARM fringe offset. The offset only appears when switching CARM_TO_ANALOG.
- Moreover, while sitting at the end of CARM_TO_ANALOG, we jiggled the common mode board gain, and suddenly the offset dropped out. I am suspecting some sort of saturation in the common mode board might be the culprit for this one.