WP Rocket 3.6.1 - Breaks CSS on Firefox

This is fixed in WP Rocket 3.6.2.1. We recommend all clients update to this version.

After updating, please go to the top admin menu > WP Rocket > Regenerate Critical CSS. After it’s done regenerating critical CSS, clear the WP Rocket cache, and then clear the Sucuri or Cloudflare cache for your site.

WP Rocket 3.6.1 may interfere with proper CSS display on Firefox browsers, and possibly Googlebot Mobile’s crawler.

If you’re seeing display issues for your site on Firefox, while logged out or in “Private browsing” mode – removing the Fallback CSS should resolve this for now.

Go to WP Rocket > Settings > File Optimization > Optimize CSS Delivery, and then delete anythin gin the “Fallback critical CSS” field. Save and then clear all caches (WP Rocket, and Sucuri/Cloudflare) and see if that helps. If it still is an issue, try disabling “Optimize CSS Delivery” completely.

WP Rocket 3.6.2 has a fix for this, but that introduced other problems - so we expect a full fix for this to be released with 3.6.2.1.