However, visitors to your live site will see the correct version. So at some point, the snapshot Google’s cache has will refer to the JavaScript file which no longer exists.

If you have enabled the Combine JavaScript files option in WP Rocket, the filename will change periodically. It takes a snapshot of your site on its own schedule - their cache is not a “live” up-to-date version of your site. Google keeps its own cache of sites, at a URL like this: : However there are a few external factors which can affect this. Under normal circumstances, you should not find 404 errors on the minified or combined files created by WP Rocket. 404 errors on minified or combined CSS/JavaScript files