Why-trade-occurs-on-next-bar

CODE:
using WealthLab.Backtest;
using System;
using WealthLab.Core;
using WealthLab.Indicators;
using System.Drawing;
using System.Collections.Generic;


namespace WealthScript4 
{
    public class MyStrategy : UserStrategyBase
    {
       public MyStrategy() : base()
        {

        }

        public override void Initialize(BarHistory bars)
        {
      indicator1 = bars.Close;
      indicator2 = new SMA(bars.Close,200);
      PlotIndicator(indicator2,Color.FromArgb(255,0,0,0));

         StartIndex = 200;
        }

        public override void Execute(BarHistory bars, int idx)
        {
         int index = idx;
         Position foundPosition0 = FindOpenPosition(0);
         bool condition0;
         if (foundPosition0 == null)
         {
            condition0 = false;
            {
               if (indicator1.CrossesUnder(indicator2, index))
               {
                  condition0 = true;
               }
            }
            if (condition0)
            {
               _transaction = PlaceTrade(bars, TransactionType.Buy, OrderType.Market, 0, 0, "Buy At Market (1)");
            }
         }
         else
         {
            condition0 = false;
            {
               condition0 = true;
            }
            if (condition0)
            {
               if (idx - foundPosition0.EntryBar + 1 >= 5)
               {
                  ClosePosition(foundPosition0, OrderType.Market, 0,"Sell after 5 bars");
               }
            }
         }

        }

   private TimeSeries indicator1;
   private IndicatorBase indicator2;
   private Transaction _transaction;
    }
}