iSupplier Allows Vendors to Delete Attachments in iSupplier After Invoice Is Approved

When testing iSupplier e-invoicing, we realized Vendors have the capability to add additional attachments, delete attachments, and modify attachments regardless of the invoice status. For us, this means a vendor can update attachments after the invoice has been reviewed and approved for payment. Has anyone else noticed this behavior? We removed all personalizations and were still seeing the behavior. We would prefer to have an Oracle backed solution as opposed to adding additional customization to iSupplier.