I noticed recently that many of the pages i’ve been working hadn’t been cached by Google for an unusually long time and that typically and probably not coincidentally those cache dates were mostly the 21st or 22nd October. I started looking at random other sites, big ones like booking.com and noticed the same thing there. Since then there has been the odd comment about it in Moz q&a’s and now it’s come to the attention of Search Engine Roundtable (https://www.seroundtable.com/google-cache-dated-19497.html) and I expect it will become a more mainstream topic in the SEO world.
So what’s going on? Googles John Mueller said “”The cached date is separate of crawling & indexing, so I wouldn’t use that as a metric”, which isn’t the most explanatory response you’ve ever heard. Is this a temporary anomaly? Is it an example of Google spending less resource on cacheing pages (unlikely if it wishes to remain the best search engine) or is it another example of something that it just doesn’t need to update the ‘customer facing’ metrics for, like PageRank, which hasn’t been updated for a year? I’m sure we’ll find out soon.