Old cron entries not removed when editing backup schedule from GUI

When editing an existing backup's schedule inside of the FreePBX GUI via Applications>Backup & Restore, upon saving, a new entry in the asterisk user crontab is written for the job (which is expected behavior), however, the old crontab entry for the original schedule (which existed before editing) is not removed.

Basically, using the GUI to modify an existing backup job's schedule will create multiple entries in cron for the same backup job.

Maybe if I had waited long enough a cleanup process would have removed the old entries, but this did persist between server reboots.  My resolution was that I manually removed the old lines from the crontab that no longer matched the current GUI backup schedule.