I believe that when a project is deleted, the assigned tasks will remain in the assignees My Tasks with no project assigned. Is there any way to prevent this when projects are being deleted? Why would that assignee ever need to keep that task in their My Tasks if the project no longer exists??? Thank you.
This is intended behavior in Asana. I believe this is to ensure that tasks that are assigned to someone are not lost if a project is inadvertently deleted.
When I delete a project that has assignees added to the tasks I first unassign all of the tasks and then delete the project. This can be easily accomplished using the bulk-edit feature.