Such behavior is desirable since we might never see ClientFinished (in case early-data is used and if the server succeeds in sending the entire response in 1-RTT).

Quote TLS 1.3 draft-18 section 4.5.1:

Although the resumption master secret depends on the client’s second flight, servers which do not request client authentication MAY compute the remainder of the transcript independently and then send a NewSessionTicket immediately upon sending its Finished rather than waiting for the client Finished.