Attached are 2 minutes of full data time series of the two ISI stages CPSs. Nothing 2hzish looking here. I zoomed in as well.
Also attached are 0.01hz bw spectra of the CPSs. Reference traces are from ~0400utc, before the comb started. Current traces are from 1200utc about 0500 local. There are some spikes around 2 hz but that are barely above the background and not only in the current traces. These don't look to be the source of this comb.