Multiple duplicate position Opened -- Issue

Hi All,

Please Help.

As per the script below, there should only be one trade execute at a spacing of 10 pips when the price is above EMA XX.. it has been working fine for the past year, but it seems that there is some issue on the starting of this weeks, which open up hundreds of duplicate position.

Is there anything wrong with the script or is a one time off bug ?

https://pepperstone.ctrader.com/images/screens/L0S6n.png

namespace cAlgo.Robots
{
    [Robot(TimeZone = TimeZones.EasternStandardTime)]
    public class xxx : Robot
    {
        [Parameter("Source")]
        public DataSeries Source { get; set; }

        [Parameter("Periods", DefaultValue = xx)]
        public int Periods { get; set; }

        [Parameter("Order Spacing (pips)", DefaultValue = 10, MinValue = 1)]
        public double OrderSpacing { get; set; }

        [Parameter("Volume", DefaultValue = 1000, MinValue = 1)]
        public int Volume { get; set; }

        private ExponentialMovingAverage ema;

        protected override void OnStart()
        {
            ema = Indicators.ExponentialMovingAverage(Source, Periods);
        }

        protected override void OnTick()
        {
            if (Trade.IsExecuting)
                return;

            double lastEma = ema.Result.Last(1);

            if (Symbol.Ask > lastEma)
            {
                OpenPosition(TradeType.Buy, OrderSpacing * Symbol.PipSize);
            }
            else
            {
                OpenPosition(TradeType.Buy, OrderSpacing * Symbol.PipSize * 100);
                //OpenPosition(TradeType.Buy, OrderSpacing);
            }
        }

        private void OpenPosition(TradeType tradeType, double orderSpacing)
        {
            foreach (Position position in Positions.FindAll("xxx"))
            {
                if ((Symbol.Ask - orderSpacing) <= position.EntryPrice && (Symbol.Ask + orderSpacing) >= position.EntryPrice)
                {
                    //Print("Open Positions: {0}", Positions.Count);
                    return;
                }
            }
        }
    }
}