Well an interesting check would be to look at one of your pages in the cache that fires an AJAX call and see where that call comes from. I agree it would be 'weird' if it came from Googlebot instead of the browser looking at the cache.
At Blekko we post process extracted pages of the crawl which, if they were putting content behind js could result in js calls offset by the initial access but 3 days seems like a long time. Mostly though the js is just page animation.
