The preload process starts to work after clearing all the cache and it stops working after all caches are created.
If you want the preload feature to work constantly, you need to enable the “Restart After Completed” option.
Why do I need this feature?
Cache is created not only with the preload feature, but also when visitors come to a page. If your site gets a lot of traffic, many caches are created concurrently due to visitors opening the pages and this causes a lot of CPU usage.
In this case, instead of clearing the entire cache and creating it all again uncontrollably, creating it in a controlled way in time will help reduce CPU usage a lot. If the option is enabled, the preload creates cache and it overwrites the existing cache file.
You are using the “Restart Preload After Completed” feature, you should disable the “New Post” option because if the “New Post” option is enabled, the entire cache is cleared when the new post is published and there is no point in using this feature.
Note: The preload feature works with the WP_CRON system. Since there will be no action to trigger WP_CRON after the entire cache has been created, you need to set a cron job as you can see in this tutorial.
Disadvantages of This Feature
Due to the cache being created one by one in time, it may take time for new changes to appear. For example; a newly published article appears only on pages whose cache has been re-created.