I have created a Member Sign-Up form that goes to a Contribution page with three price sets (one is always hidden with JS, so two appear). Under the Contribution Page's settings, "Use a confirmation page?" is checked. When valid input is submitted, the Confirmation page that comes up next has no visible content. In the HTML a form with the id "Confirm" is shown, but it has only hidden inputs and no submit button.
Does anyone know why this is happening? How can I get a normal confirmation page to appear?
This is testable at http://aplddemo.wpengine.com/sign-up/?type=student
To make this issue even more unusual, after creating a different (test) Contribution page and completing a transaction on that, the original confirmation page began working. My immediate issue is solved, but I'm still curious why this happened and what is to prevent it from happening again.
UPDATE - September 1
This issue reappeared. This time I added ini_set('display_errors', true); to my plugin, and see errors like the following:
Warning: include(/nas/wp/www/cluster-40204/aplddemo/wp-content/plugins/files/civicrm/templates_c/en_US//%%3D/3D1/3D13F2BA%%Main.tpl.php): failed to open stream: No such file or directory in /nas/wp/www/cluster-40204/aplddemo/wp-content/plugins/civicrm/civicrm/packages/Smarty/Smarty.class.php on line 1907
Warning: include(): Failed opening '/nas/wp/www/cluster-40204/aplddemo/wp-content/plugins/files/civicrm/templates_c/en_US//%%3D/3D1/3D13F2BA%%Main.tpl.php' for inclusion (include_path='/nas/wp/www/cluster-40204/aplddemo/wp-content/plugins/files/civicrm/custom_ext/com.osseed.eventcalendar-1.1/:/nas/wp/www/cluster-40204/aplddemo/wp-content/plugins/files/civicrm/custom_ext/ca.bidon.civiexportexcel/:/nas/wp/www/cluster-40204/aplddemo/wp-content/plugins/files/civicrm/custom_ext/nz.co.fuzion.extendedreport/:/nas/wp/www/cluster-40204/aplddemo/wp-content/plugins/files/civicrm/custom_ext/co.johnwebster.apld/:/nas/wp/www/cluster-40204/aplddemo/wp-content/plugins/files/civicrm/custom_ext/org.civicrm.module.cividiscount/:.:/nas/wp/www/cluster-40204/aplddemo/wp-content/plugins/civicrm/civicrm:/nas/wp/www/cluster-40204/aplddemo/wp-content/plugins/civicrm/civicrm/packages:.:/nas/wp/www/cluster-40204/aplddemo/wp-content/plugins/civicrm/civicrm/:/nas/wp/www/cluster-40204/aplddemo/wp-content/plugins/civicrm/civicrm//packages:.:/usr/sha in /nas/wp/www/cluster-40204/aplddemo/wp-content/plugins/civicrm/civicrm/packages/Smarty/Smarty.class.php on line 1907
I thought it might be a caching issue, so I went to Administer > System Settings > Cleanup Caches and Update Paths, but clicking the "Cleanup Caches" button doesn't affect the error. The issue changes periodically. Sometimes parts of the form appear, with an error about the missing compiled Smarty template where the price field should be. I haven't been able to connect the change in the error's behavior/message to any other changes on the site. They seem to happen on their own.
