The Recycle bin saves deleted Activities or Resources from your Moodle course for a period of seven days. After an Activity or Resource is deleted, it can take up to 15 minutes to appear in your Recycle bin and up to 15 minutes to be restored into your course from the Recycle bin. If the items in the Recycle bin are not restored or retrieved during this period, they will be permanently deleted after seven days.
Note: If you have deleted an Activity wth a grade associated with it, you may see a warning in your Gradebook that will let you know that the Activity and associated grades is being deleted. Additionally, the column of that activity on your Grader report will say: [Deletion in progress] [Name of the Activity and Resources].
Once the Activity is deleted and stored on your Recycle bin the warning will disappear.
While the Recycle bin feature is robust, it still has its exemptions.