If you bypass each IC separately, what attenuation do you see for each IC?
Pin #11 is driven by the output of an OP284 op amp (unless I've incorrectly identified the pinout). Does the voltage on this pin vary during the self test? I expect that pin #11 is an analogue control pin.
Have you tried matching the pinout to other 1GG7-nnnn parts at keysight.com?