Assert that FetchWithCriteria is called from the update thread

osu.Game/Online/Leaderboards/LeaderboardManager.cs

@@ -7,6 +7,7 @@ using System.Diagnostics;
 using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
+using osu.Framework.Development;
 using osu.Framework.Graphics;
 using osu.Framework.Logging;
 using osu.Game.Beatmaps;
@@ -24,7 +25,11 @@ namespace osu.Game.Online.Leaderboards
 {
     public partial class LeaderboardManager : Component
     {
+        /// <summary>
+        /// The latest leaderboard scores fetched by the criteria in <see cref="CurrentCriteria"/>.
+        /// </summary>
         public IBindable<LeaderboardScores?> Scores => scores;
+
         private readonly Bindable<LeaderboardScores?> scores = new Bindable<LeaderboardScores?>();
 
         public LeaderboardCriteria? CurrentCriteria { get; private set; }
@@ -47,6 +52,9 @@ namespace osu.Game.Online.Leaderboards
         /// </summary>
         public void FetchWithCriteria(LeaderboardCriteria newCriteria, bool forceRefresh = false)
         {
+            if (!ThreadSafety.IsUpdateThread)
+                throw new InvalidOperationException(@$"{nameof(FetchWithCriteria)} must be called from the update thread.");
+
             if (!forceRefresh && CurrentCriteria?.Equals(newCriteria) == true && scores.Value?.FailState == null)
                 return;
 

osu.Game/Screens/Ranking/SoloResultsScreen.cs

@@ -54,7 +54,8 @@ namespace osu.Game.Screens.Ranking
                 if (globalScores.Value != null && leaderboardManager.CurrentCriteria?.Equals(criteria) == true)
                     requestTaskSource.TrySetResult(globalScores.Value);
             });
-            leaderboardManager.FetchWithCriteria(criteria, forceRefresh: true);
+
+            Schedule(() => leaderboardManager.FetchWithCriteria(criteria, forceRefresh: true));
 
             var result = await requestTaskSource.Task.ConfigureAwait(false);