Screener-to-trigger-on-gap

Hi,
I would like to create a scanner for gaps up/down. I used a building block strategy on SPY using a specific date range where I know there is a gap up (22 and 23d August 2023). So building block reads buy at market, gap up at bar open. I put an arbitrary sell after 8 bars to test. If I tun a backtest it successfully picks up the gap, buy and sells.
I then open it as a c# coded strategy and add the line for it to be a scanner and rerun the test. Im expecting it to alert if it successfully identifies the gap but this doesnt work.

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


namespace WealthScript5 
{
    public class MyStrategy : UserStrategyBase
    {
       public MyStrategy() : base()
        {

            StartIndex = 0;
        }

        public override void Initialize(BarHistory bars)
        {

            foreach(IndicatorBase ib in _startIndexList)
                if (ib.FirstValidIndex > StartIndex)
                    StartIndex = ib.FirstValidIndex;
        }

        public override void Execute(BarHistory bars, int idx)
        {
         if (idx < bars.Count - 1) return;
         int index = idx;
         Position foundPosition0 = FindOpenPosition(0);
         bool condition0;
         if (foundPosition0 == null)
         {
            condition0 = false;
            {
               if (bars.IsGapUp(index))
               {
                  condition0 = true;
               }
            }
            if (condition0)
            {
               _transaction = PlaceTrade(bars, TransactionType.Buy, OrderType.Market, 0, 0, "Buy At Market (1)");
            }
         }
         else
         {
            condition0 = false;
            {
               pos = LastOpenPosition;
               if (pos == null || (index - pos.EntryBar) >= 8)
               {
                  condition0 = true;
               }
            }
            if (condition0)
            {
               Backtester.CancelationCode = 108;
               ClosePosition(foundPosition0, OrderType.Market, 0, "Sell At Market (1)");
            }
         }

        }

        public override void NewWFOInterval(BarHistory bars)
        {

        }

      private Position pos;

      private Transaction _transaction;
        private List<IndicatorBase> _startIndexList = new List<IndicatorBase>();
    }
}