deep-copy-subject-mode attribute on Security Subsystem is Readable to all roles

[standalone@localhost:9990 /] :whoami(verbose=true)
{
    "outcome" => "success",
    "result" => {
        "identity" => {
            "username" => "monitor",
            "realm" => "ManagementRealm"
        },
        "roles" => ["Monitor"]
    }
}
[standalone@localhost:9990 /] /subsystem=security:read-attribute(name=deep-copy-subject-mode)
{
    "outcome" => "success",
    "result" => false
}