After making core updates in Drupal commons, from 7.37 to 7.50, scheduled Civi mails are not being sent. Cron jobs are still set up. Before this update, we've been using it for years with no known issues. Using CiviCRM 4.8.7. Currently trying to upgrade now but there are other roadblocks also.
Watchdog shows the following error for the time of the scheduled mailing:
error cron EntityMalformedException: Missing bundle property on entity of type node. in entity_extract_ids() (line 7953 of /var/www/html/example/docroot/includes/common.inc).