Not sure if this has been addressed and dont believe this is a bug, but the player you get from playing the 40 stamina reward events are random.   I've been playing the Wise and Byard events exclusively - thinking if I managed to pull a player it would be the player in the event, however pulled a Suh from the Wise event.   

So if you are interested in pulling a certain player, just play the easiest event and hope.