Sudarshan, Matt
The new ISS filter was seen to oscillate at ~1MHz with no input signal. This was fixed by adding 50pF cap into the feedback of the output opamp. This cap, in combination with the 10k resistor, puts a pole at 300kHz, which is fine for this loop. The second loop is currently closed (with the IFO at high power) and appears to be working properly.
Also, independently of the repair that Matt desribed above, we found that an op-amp in the very first stage kept railing at -10 V. It is AD620 stuffed in U10 of the 2nd loop servo box (D1300439-v2). We have no idea when this op-amp had died. Swapping the op-amp with a spare in the EE shop fixed the issue. We will update the e-traveler accordingly.