Late last night I found this article on Ziptie by Tomasz Rudzki. In it he details specific sites that would over various weekends disappear from results only to bounce back by Monday. He did a compare and contrast to what those sites share in common.
Google has come forward to confirm its an “issue”. And as always with zero explanation.
I went back to do a cursory check on those dates from the indexation data log and found evidence that its not a bug, its a feature.
If you aren’t a member, and have been considering joining this discussion at some point, now is a good time. I’m going to be working on a deeper comparison and analysis.