It is a good habit to check the application log for Errors logged from the Scheduling service.
You can let the system send you an e-mail on a regular basis when those errors occur.
See the topic ‘Subscribe for e-mails on certain application logs’
Special attendance is required for scheduled task that have a time frame configured too short.
When a running task is being aborted because it is not ready when the configured time is elapsed the running proces can end up in an unexpected state.
The check is done in General Settings - Scheduled tasks - - Queues tasks
In this example this task is running every 5 minutes. It is finished within 2 minutes. So that one is oke.