TheMadScientist - 12:31 pm on Dec 13, 2012 (gmt 0)
The big problem I have with this theory is that surely it's been going on too long for that. It seems like as long as some people have been seeing this on their sites, Google would have learned everything they needed to know.
That's exactly where my theory about sites (pages) 'getting stuck' came from ... One thing we need to keep in mind with these type of things is it's a heuristic, not people, making the determination and there could be a some 'threshold' (for lack of a better word) somewhere in it that's causing sites (pages) with certain characteristics to be 'retested' even though to someone looking at stats it seems like there shouldn't be any need to 'check again'.
IOW: They 'get stuck' in the 'test mode' of the algo for some reason.
That would also explain why some people like Shaddows are not seeing it any more ... If at some point there were changes to the site (or even visitor behavior WRT the site) that removed the 'need to test this' trigger inadvertently, the 'zombies' would 'disappear' from the stats.