There is a known behavior in the Advanced Routing's email notifications, where the message doesn't contain the transformed file name, but the original input file's name.

The following example demonstrates the circumstances where this behavior will appear:

An Advanced Routing Route is configured with a transformation type Step (i.e. PGP Encrypt) and a Send to Partner Steps

The email notifications must be enabled; for example - "Notify following e-mails on route success" using a default mail template RoutingSucceededNotification.xhtml

A file named test.txt arrives for processing

The file is PGP encrypted by the PGP Encrypt Step and the name of the resulting file is text.txt.pgp

The new file text.txt.pgp is sent out by the Send To Partner Step

An email notification is sent and in its body the processed file's name is shown as text.txt instead of text.txt.pgp

At the present time no workaround or a fix exists to correct this behavior.