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Troubleshooting Intermittent Page Display Issues with WP-Optimize Cache

28 threads Sep 16, 2025

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Many users of the 'WP-Optimize – Cache, Compress images, Minify & Clean database to boost page speed & performance' plugin report a common but frustrating problem: their website pages intermittently display incorrectly. The issues range from pages appearing as raw code, missing CSS, broken headers/footers, or grids not loading. Often, the problem is temporarily resolved by clearing the cache, only for it to reappear hours or days later.

This guide will explain why these issues occur and provide the most common, effective solutions based on community reports and resolutions.

Why Do These Intermittent Display Issues Happen?

Based on numerous support threads, these problems are rarely due to a single cause. The intermittent nature often points to conflicts or specific conditions under which the cached page becomes corrupted or is served incorrectly. Common root causes include:

  • Conflicts with Other Plugins or Themes: Page builders like Elementor, WPBakery, or themes like Divi can sometimes have complex JavaScript or CSS that doesn't play nicely with caching or minification processes.
  • Aggressive Minification or Merging Settings: While minifying CSS and JS files can improve speed, it can also break scripts if not configured correctly, especially for sites that already support HTTP/2.
  • Automatic Cache Purging Events: The plugin is designed to purge cache automatically when content is updated. However, certain events (e.g., WooCommerce stock updates, comment approvals) can sometimes cause broader-than-expected purges or corrupt existing cache files.
  • Server or Hosting Environment: Specific server configurations, file permissions, or existing server-level caching (e.g., on hosts like GoDaddy or WordPress.com) can conflict with the plugin's cache.
  • Lifespan of Minified Cache: An expired or corrupted minified cache can lead to CSS or JS files returning 404 errors or serving incorrect MIME types, making a site look broken.

Most Common and Effective Solutions

If your site is experiencing these random display glitches, work through these solutions in order.

1. Disable Minification and Merging (Temporarily)

The most frequent culprit for broken styling is the minify function. As a first step, completely disable minification for CSS, JavaScript, and HTML.

  • Go to WP-Optimize > Minify.
  • Ensure all options for enabling minification are turned OFF.
  • Clear the entire cache (WP-Optimize > Cache > Purge cache) and purge minified files (WP-Optimize > Minify > Minified status > Purge the minified files).

If this fixes the issue, your site likely does not need minification, especially if it uses HTTP/2. You can leave it disabled or carefully re-enable options one by one to find the specific conflict.

2. Identify and Isolate Plugin Conflicts

A conflict with another plugin is a common cause. To test this:

  • Temporarily deactivate all other plugins except WP-Optimize.
  • Clear your cache and see if the problem persists.
  • If the issue is resolved, reactivate your plugins one by one, clearing the cache each time, to identify the conflicting plugin.
  • Once identified, you can often find a workaround, such as excluding the plugin's scripts from minification or caching.

3. Check for a Cache Lifespan Setting

A corrupted cache can cause pages to display incorrectly. If your minified cache has a lifespan set, it will automatically regenerate when it expires. If this process fails, it can cause issues.

  • Go to WP-Optimize > Minify > Advanced settings.
  • Check the 'Cache lifespan' setting. Setting it to 0 means it never expires, which can sometimes be more stable than frequent automatic regeneration.
  • Experiment with different values or set it to 0, then purge all caches.

4. Exclude Problematic Pages from Caching

If the issue only occurs on specific pages (e.g., a checkout page, a page with a complex grid), the most straightforward solution is to exclude those pages from being cached altogether.

  • Go to WP-Optimize > Cache > Advanced settings.
  • Add the URLs of the problematic pages to the 'URLs to exclude from caching' field.
  • Save changes and purge the cache.

5. Enable Debugging to Find Errors

Intermittent issues can sometimes throw PHP errors that are not visible to users. Enabling WordPress debugging can help you see these errors and pinpoint the exact problem.

  • You can use a plugin like WP Debugging to enable debugging safely.
  • Once enabled, recreate the issue by waiting for a page to break. The error log may reveal a specific script or process that is failing, giving you a clear direction for a solution (e.g., excluding a specific file).

Conclusion

Intermittent page display issues with WP-Optimize are almost always solvable by methodically working through your settings. Start by simplifying your configuration (disabling minification), then move on to isolating conflicts, and finally use tools like page exclusion and debugging to handle stubborn cases. Remember to always clear your cache after changing any settings.

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