Ctools1.18 / 1.19 breaks rule "content is viewed" if page is a panel. Easily recreatable with just panels, ctools and rules.

Ok, actually narrowed down the change that caused the problem..

In 1.17 ctools\page_manager\plugins\tasks\node_view.inc

/**
 * Entry point for our overridden node view.
 *
 * This function asks its assigned handlers who, if anyone, would like
 * to run with it. If no one does, it passes through to Drupal core's
 * node view, which is node_page_view().
 */
function page_manager_node_view_page($node) {
  // Prep the node to be displayed so all of the regular hooks are triggered.
  // Also save the output for later, in case it is needed.
  $default_output = node_page_view($node);

  // Load my task plugin
  $task = page_manager_get_task('node_view');

  // Load the node into a context.
  ctools_include('context');
  ctools_include('context-task-handler');

  // Load all contexts.
  $contexts = ctools_context_handler_get_task_contexts($task, '', array($node));

  // Build the full output using the configured CTools plugin.
  $output = ctools_context_handler_render($task, '', $contexts, array($node->nid));
  if ($output !== FALSE) {
    node_tag_new($node);
    return $output;
  }

  // Try loading an override plugin.
  foreach (module_implements('page_manager_override') as $module) {
    $call = $module . '_page_manager_override';
    if (($rc = $call('node_view')) && function_exists($rc)) {
      return $rc($node);
    }
  }

In 1.19 ctools\page_manager\plugins\tasks\node_view.inc

/**
 * Entry point for our overridden node view.
 *
 * This function asks its assigned handlers who, if anyone, would like
 * to run with it. If no one does, it passes through to Drupal core's
 * node view, which is node_page_view().
 */
function page_manager_node_view_page($node) {
  // Load my task plugin
  $task = page_manager_get_task('node_view');

  // Load the node into a context.
  ctools_include('context');
  ctools_include('context-task-handler');

  // Load all contexts.
  $contexts = ctools_context_handler_get_task_contexts($task, '', array($node));

  // Build the full output using the configured CTools plugin.
  $output = ctools_context_handler_render($task, '', $contexts, array($node->nid));
  if ($output !== FALSE) {
    node_tag_new($node);
    return $output;
  }

  // Try loading an override plugin.
  foreach (module_implements('page_manager_override') as $module) {
    $call = $module . '_page_manager_override';
    if (($rc = $call('node_view')) && function_exists($rc)) {
      return $rc($node);
    }
  }

  // Prepare the node to be displayed so all of the regular hooks are triggered.
  $default_output = node_page_view($node);

I'm postponing this as I don't know if this is a necessary and permanent change in ctools. I don't understand any of it to be honest.. I just know that swapping that file lets "content is viewed" work again.