If a learner has initiated a task to send to an assessor, the timing of its delivery is controlled by a behind the scenes task called a cron job. Typically the default setup is for the cron job (send-queued-notifications) to run every 10 minutes. This means if a learner initiates a task using the complete and confirm via email method at 8:30, the assessor might not receive the task until 8:40. If this timing should be adjusted, you must speak with a developer at your institution.