SevenCubed - 4:49 pm on Nov 4, 2012 (gmt 0)
These days it's really difficult to know anything with certainty regarding google. My GUESS would be that it is just the behaviour that google exhibits after a site structure change. It's typically dropped back to a staging region in the SERPs, reassessed, then floated back to the area where it used to be if the changes aren't too drastic. That has always been my experience with changes going back even 4-5 years ago. I doubt it has anything to do with the google turmoil of recent times. In the past I knew I might have to wait as much as 3 weeks for it to bounce back -- these days I have no idea what the timeline might be.
Out of curiosity have you noticed if your home page has been replaced with an inner page and that page appears maybe somewhere around page 7 (no not because I love that number!) in the SERPs?