Use single method for starting/restarting spectator screen

osu.Game/Screens/OnlinePlay/Multiplayer/Multiplayer.cs

@@ -21,7 +21,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
         {
             base.OnResuming(last);
 
-            if (client.Room != null)
+            if (client.Room != null && client.LocalUser?.State != MultiplayerUserState.Spectating)
                 client.ChangeState(MultiplayerUserState.Idle);
         }
 

osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerMatchSubScreen.cs

@@ -406,29 +406,22 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
             }
         }
 
-        private void onRoomUpdated() => Scheduler.Add(() =>
+        private void onRoomUpdated()
         {
-            if (client.Room == null)
+            Scheduler.AddOnce(UpdateMods);
-                return;
+        }
-
-            Debug.Assert(client.LocalUser != null);
-
-            UpdateMods();
-
-            if (client.LocalUser.State == MultiplayerUserState.Spectating
-                && (client.Room.State == MultiplayerRoomState.Playing || client.Room.State == MultiplayerRoomState.WaitingForLoad)
-                && ParentScreen.IsCurrentScreen())
-            {
-                StartPlay();
-
-                // If the current user was host, they started the match and the in-progress operation needs to be stopped now.
-                readyClickOperation?.Dispose();
-                readyClickOperation = null;
-            }
-        });
 
         private void onLoadRequested()
         {
+            // If the user is spectating, the multi-spectator screen may still be the current screen.
+            if (!ParentScreen.IsCurrentScreen())
+            {
+                ParentScreen.MakeCurrent();
+
+                Schedule(onLoadRequested);
+                return;
+            }
+
             StartPlay();
 
             readyClickOperation?.Dispose();

osu.Game/Screens/OnlinePlay/Multiplayer/Spectate/MultiSpectatorScreen.cs

@@ -140,6 +140,13 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Spectate
             leaderboard.RemoveClock(userId);
         }
 
+        public override bool OnBackButton()
+        {
+            // On a manual exit, set the player state back to idle.
+            multiplayerClient.ChangeState(MultiplayerUserState.Idle);
+            return base.OnBackButton();
+        }
+
         private int getIndexForUser(int userId) => Array.IndexOf(userIds, userId);
     }
 }