When service consumption cpu time message will be at the journal?

[u34@xxxxxxx]

Hello,
I have timers to run user, and system, services.
Usually, but not always, the journal has a 

    systemd[1]: NAME.service: Consumed DURATION CPU time.

as the last message for each activation of a service. I wonder whether it 
is expected that sometimes there is no such message. I can not predict, 
or characterise, when such message will not be given, other than saying 
I suspect the user service is more likely to not have such a message.

I currently run systemd 253.5, but seen that at previous versions too.

--
u34