Unscheduling a scheduled (cron-) Job is not being persisted. Therefore old cron jobs reappear after some time. Events are fired multiple times.
I encountered this bug with AEM-6.2. Cronjobs are unusable this way. I must remove corresponding nodes under /var/eventing/scheduled-jobs to get rid of them.
Please notice attached simple app with two components. CronScheduler should schedule/unschedule 1 cron job on activation/deactivation. CronProcessor simply consumes the events and logs.
When manually deactivating the CronScheduler-Component all seems fine in the first place, but after some time old cron-jobs reappear for they have never been removed from the repository.
To reproduce deactivate/activate the CronScheduler-Component some times and you get multiple instances of the same cron-Job.