Scheduled Posts are published in WordPress through a WP cron job. Normally, WordPress triggers the cron job each time a request hits the backend. The backend is rarely hit, however, when using a cache, which causes scheduled posts to publish late.

LSCWP will correctly purge the cache when a scheduled post is published in the cron job. All you need to do is make sure that you can reliably hit the backend. This can be done by scheduling a cron job to hit wp-cron.php at your ideal interval.

For Example, to update scheduled posts every 15 minutes:

*/15 * * * * wget http://your_wp_site/wp-cron.php

When using a server level cron job, WordPress suggests defining DISABLE_WP_CRON in your wp-config file to disable checking wp-cron on a backend hit.

define('DISABLE_WP_CRON', true);

This may be useful in reducing the number of calls made to wp-cron if that is desired.

For a more in-depth discussion of this issue, see our blog.