I recently discovered this weird behaviour by drush when I disabled Comment module in Drupal 7 - drush was giving the following warning whenever I tried enabling/disabling any module:
WD actions: 3 orphaned actions (comment_publish_action, comment_save_action, comment_unpublish_action) exist in the actions table. Remove orphaned actions
After some scrounging on drupal.org (where most solutions were meant for Drupal 6), I found the solution at http://blog.devkinetic.com/node/9 Just execute the following once:
drush php-eval "actions_synchronize(actions_list(), TRUE);"