The canned response is specific to the email body, and the subject line remain unchanged. The subject line displayed will be the one configured in the email template within the process. This is the expected behaviour of the product. but it is not confusing that there is a field for configuring the subject on for any canned response.
As user I would expect the subject line to be updated accordingly to the Canned Response selected. Enate vendor with the reference number 8033396-T.