This happens in my custom Zen-based theme where I made a custom node type 'events'. I put print_r($node) inside of my node-events.tpl.php which gave all the ckk fields including the ones that didn't turn into HTML i.e. not displayed.
When viewing this type of node in a stock drupal theme, this problem doesn't occur so everything gets displayed as desired. This means my viewing permissions are in check and also under admin->content type-> 'events' -> display fields hidden is turned off (set to standard just the way it was when I didn't have the problem)