As you know, there has been another wave of mobile-first index moves over this weekend and some are noticing that when a site is moved, if you try to access the Google Cache of that site, Google returns a 404 page not found error.
I was able to replicate it myself on a couple sites that were moved over the weekend and this is what the Google cache link from the Google search results return:
John Mueller from Google said what he always says about the Google cache issues, not to worry about it. Aleyda Solis asked John about it and John responded on Twitter saying “sometimes these take a bit of time to catch up – it doesn’t affect crawling, indexing, ranking though, so no need to worry.”
Sometimes these take a bit of time to catch up – it doesn’t affect crawling, indexing, ranking though, so no need to worry 🙂
— John ☆.o(≧▽≦)o.☆ (@JohnMu) May 28, 2018
Again, this is a typical answer from John around the Google Cache. The cache is sometimes a bit slower, out dated and often confused from how I read John’s responses around issues with the Google Cache.
Forum discussion at Twitter.