Yesterday, 19-MAR-2013 we collected data between two stores with HV in physics mode.
We lowered the voltage in Disc5 quad A by 50 V and raised Disc5 quad C by 120 V. Once we finished the exercise we placed the voltages back to their nominal values. A summary for the biggest run is shown below:

The only feature in these plots that was present in Devika's runs is the blob (four spikes) in disc 5 quad A. Lowering the voltage by 50 V did not make it go again. The spikes seen in other discs during Devika's runs are not there any more but new ones have appeared in other locations. There are some indications that disc 5 quad C has more activity, but actual changes need actual collisions running at the higher voltages we used for this test run. 
The fact that the spikes moved between the test runs casts some doubt on my assertion that they were related to actual ionization activity inside the detectors, unless GEM have such feature that one hole or several nearby could go on corona mode in random locations.
I'm now focusing on the disc 5 quad A four spike blob. Akio's monitor shows disc 5  in run 14078014 getting into a mode that shows many slow low amplitude pulses (almost a sine wave):

The scope traces collected by Akio's QA show the ofending pulses:

I tried to find those pulses in our test run (14078036) but have been unsuccesful so far, the pulses I see look rather conventional: