"403 FORBIDDEN "Cannot delete as there are resources associated with the project." Error id: <id>".
Users that either delete a project or use the Change project action with an active directory integration attached to the project will encounter this issue.
This is because Active Directory does not listen to events that happen from Project Service. So events such as deletion of a project and the changing of resources from one project to another in regards to the active directory are not propagated on the active directory side. They only take place on the project side; thus, we end up in an inconsistent state where the database in active directory does not reflect the changes made to the projects.