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.