Fix leaderboard showing placeholder briefly when entering song select

osu.Game/Screens/Select/Leaderboards/Leaderboard.cs

@@ -40,6 +40,8 @@ public class Leaderboard : Container
 
         private ScheduledDelegate showScoresDelegate;
 
+        private bool scoresLoadedOnce;
+
         private IEnumerable<Score> scores;
         public IEnumerable<Score> Scores
         {
@@ -48,6 +50,8 @@ public IEnumerable<Score> Scores
             {
                 scores = value;
 
+                scoresLoadedOnce = true;
+
                 scrollFlow?.FadeOut(fade_duration, Easing.OutQuint).Expire();
                 scrollFlow = null;
 
@@ -227,6 +231,10 @@ private void handleApiStateChange(APIState oldState, APIState newState)
 
         private void updateScores()
         {
+            // don't display any scores or placeholder until the first Scores_Set has been called.
+            // this avoids scope changes flickering a "no scores" placeholder before initialisation of song select is finished.
+            if (!scoresLoadedOnce) return;
+
             getScoresRequest?.Cancel();
             getScoresRequest = null;