[Fix] Flag bug

Assets/Scripts/Core/BoardService.cs

@@ -251,12 +251,13 @@ namespace Minesweeper.Core
             while (queue.Count > 0)
             {
                 var cell = queue.Dequeue();
-                if (visited[cell.X, cell.Y] || cell.IsMine || cell.IsFlagged)
+                if (visited[cell.X, cell.Y] || cell.IsMine)
                 {
                     continue;
                 }
 
                 visited[cell.X, cell.Y] = true;
+                ClearFlag(cell);
                 OpenSafeCell(cell);
 
                 if (cell.NeighborMines != 0)
@@ -274,7 +275,7 @@ namespace Minesweeper.Core
                         }
 
                         var neighbor = cells[x, y];
-                        if (!visited[x, y] && !neighbor.IsMine && !neighbor.IsFlagged && !neighbor.IsOpened)
+                        if (!visited[x, y] && !neighbor.IsMine && !neighbor.IsOpened)
                         {
                             queue.Enqueue(neighbor);
                         }
@@ -295,6 +296,17 @@ namespace Minesweeper.Core
             AddChangedCell(cell);
         }
 
+        private void ClearFlag(CellData cell)
+        {
+            if (!cell.IsFlagged)
+            {
+                return;
+            }
+
+            cell.IsFlagged = false;
+            FlaggedCellsCount--;
+        }
+
         private void AddChangedCell(CellData cell)
         {
             changedCells.Add(ToData(cell));