Thanks! the problem is for my code no from nuggeta. the leaderboard work good! the fault is:
i open the game, go to the scene "leaderboard", the leaderboard is load correctly, press button "back" and go to menu and if now i want see scores again on "leaderboard" the leaderboar dont load.. only can load 1 time :/
EDIT: only work if i go from "menu" to "leaderboard" and now press back, go to menu and again press on leaderboard, dont work if i go to "play" scene