Cron job fails to execute PHP script after number of days

I have a couple cron jobs set up to launch a batch process twice a day. I'm currently using AWS Elastic Beanstalk to handle all the deployments. After a deployment, the cron jobs successfully execute the PHP script for about 10 days. Then, they suddenly stop running. After inspection of the cron logs, I can see the cron command being executed as normal -- but the script never runs.