Scheduled job to clear leftover data after deleting a user from Unsynced from Directory

At times, deleting a user from an external directory does not remove all the records/data belonging to that user. In this case, Confluence does not allow the user to be removed from Unsynced from Directory due to the existing record/data which is still referencing to the user. As an example, an issue is reported whereby few users are unable to remove from Unsynced from Directory as follows:

1. A user is attempted to be removed from Unsynced from Directory
2. This attempt failed and causes the following error:

   javax.persistence.EntityNotFoundException: deleted object would be re-saved by cascade (remove deleted object from associations): [com.atlassian.confluence.security.SpacePermission#93022608]

3. The error shown above is mentioning that the user still has specific space permissions
4. Due to that, Confluence does not allow the user to be removed from Unsynced from Directory

Though this kind of issue does not always re-occur, it would be better if there is a scheduled job that will remove all records/data belonging to deleted users from an external AD.