Fix callback potentially not getting fired

osu.Game/Screens/Select/BeatmapClearScoresDialog.cs

@@ -29,7 +29,7 @@ public BeatmapClearScoresDialog(BeatmapInfo beatmap, Action onCompletion)
                     Action = () =>
                     {
                         Task.Run(() => scoreManager.Delete(scoreManager.QueryScores(s => !s.DeletePending && s.Beatmap.ID == beatmap.ID).ToList()))
-                            .ContinueWith(t => Schedule(onCompletion));
+                            .ContinueWith(_ => onCompletion);
                     }
                 },
                 new PopupDialogCancelButton

osu.Game/Screens/Select/SongSelect.cs

@@ -625,7 +625,9 @@ private void clearScores(BeatmapInfo beatmap)
         {
             if (beatmap == null || beatmap.ID <= 0) return;
 
-            dialogOverlay?.Push(new BeatmapClearScoresDialog(beatmap, () => BeatmapDetails.Leaderboard.RefreshScores()));
+            dialogOverlay?.Push(new BeatmapClearScoresDialog(beatmap, () =>
+                // schedule done here rather than inside the dialog as the dialog may fade out and never callback.
+                Schedule(() => BeatmapDetails.Leaderboard.RefreshScores())));
         }
 
         public override bool OnPressed(GlobalAction action)