Aggregated CSS & JS files revert to old version I'm troubleshooting an odd issue on my Drupal 7 site where it seems that old versions of our aggregated CSS &amp; JS files are used some amount of time after a cache clear. How this is playing out is that I'll make some update to our CSS or JS, then clear the cache via drush cc all (I've also used the UI to manually clear the cache). I get an updated version of the CSS / JS for a while. At some point (typically I've noticed it a few hours later), the page serves the old version of the aggregated file.

I've pulled mysqldumps of the site, and can see that the values in the variable table for drupal_css_cache_files, for example, contain a reference to the old aggregate rather than the new. 

I found this issue on drupal.org (and I'm not sure it's exactly the same thing), but one of the suggestions involves deleting all files in &lt;root&gt;/cache, which I don't have. Would this be the same as deleting the files in sites/default/files/js/?

Another part of this that may or may not be related is that I see in my site logs "page not found" requests for old aggregated files that don't exist anymore.

I'm hitting a wall in troubleshooting, since it seems like the actual database value for the new aggregated file is being reverted. Anyone know what might be going on here?
Couple things to look into. An external cache (Varnish/Boost/etc...) could be referencing the old files. This issue will help with the variable_set's with css/js aggregation https://www.drupal.org/node/886488#comment-9668583. Also see this issue: https://www.drupal.org/node/1014086. I'd guess it's an external caching issue based off of what your describing but I can't say for sure due to the flaws in core that have still not been fixed.

In all honesty advagg will fix these issue for you. Drupal.org uses it due to issues with deployments https://www.drupal.org/node/1412130 https://www.drupal.org/node/2446971