Two weeks ago, I flew on standby and got the bonus on one flight, but not the other.
I bcouldn't SDC as one was oversold. At the airport, I went to the checkin counter and got a departure management card for the first flight. For the second flight, they could confirm me in F. It posted F/F and I got the 50% EQM and RDM bonuses. I cleared the standby list for the other flight at the gate. I got a coach seat, and it showed up as T/T (rather than Y/Y or Y/T)