Everything old is new again! 

In casual conversation this morning with Cheryl V. and Jeff B, the possible link to cryopump frost flakes falling off of the inner reserviors of the site's cryogenic pumps being a possible source of the unexplained IFO glitches seemed to have been "news" to them.  In the distant past, it had been common knowledge that glitches might be resulting from frost flakes falling off of the surfaces of the inner vessel of the 80K pumps.  Glitches could result from the flakes crossing the beam as particulates or effecting the beam when they were evaporated upon contacting the relatively warm vacuum vessel surfaces. 

We know that "liberating frost flakes" result when we hard close the GVs or otherwise bang on vacuum equipment near the 80K pumps.  We have seen pressure spikes from the evaporated frost followed by the tell-tale pump down curve for some large cases of this.  It is unknown to what degree that this is happening for events too small to see by the pressure gauges.  Meaning, not seeing this in the pressure data may not exclude the possibility that it is still happening at IFO-impacting levels too small to see with the gauges. 

Cheryl V. asked that aLOG theory as it may be of interest to others.