Closing one position seems to close them all with same Symbol

I've encountered an issue with cTrader where closing a position with a specific label seems to close all positions.

Example code below which reproduces the issue.

Why is every position closed when we explicitly look for positions with the specific label and trade type?

using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net;
using System.Runtime.InteropServices;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading;
using System.Threading.Tasks;
using System.Timers;
using cAlgo.API;
using cAlgo.API.Indicators;
using cAlgo.API.Internals;
using cAlgo.Indicators;

    /// <summary>
    /// Add 2 instances of this bot in cTrader with the Ger30 symbol. Put both instances in the M1 time frame.
    /// In one instance, select "Sell" for the parameter; for the other instance, select "Buy".
    /// Start both instances.
    /// Look at the log. Two different position labels.
    /// Now in the TradeWatch window, click the close "X" button next to the bottom-most listed position.
    /// Both positions get closed!
    /// This is NOT expected behaviour since we only close one position and expecially search for historical trades on the specific trade type and label.
    /// </summary>

namespace cAlgo.Robots
{
    [Robot(TimeZone = TimeZones.UTC, AccessRights = AccessRights.FullAccess)]
    public class BugBot : Robot
    {
        [Parameter("Trade Type", Group = "Trade Settings", DefaultValue = TradeType.Sell)]
        public TradeType TradeTypeForBot { get; set; }

        private string _positionLabel = "Bug bot";

        protected override void OnStart()
        {
            Positions.Closed += Positions_Closed;

            _positionLabel += TradeTypeForBot;
            Print("OnStart: Starting \"{0}\"", _positionLabel);
            TradeResult r = ExecuteMarketOrder(TradeTypeForBot, Symbol.Name, 0.1, _positionLabel, 10, null, null, false);
        }

        /// <summary>
        /// Runs when a position is closed.
        /// </summary>
        /// <param name="args"></param>
        private void Positions_Closed(PositionClosedEventArgs args)
        {
                Position p1 = args.Position;
            //Search for the specific label and trade type of this position so we don't close similar ones.
                HistoricalTrade ht = History.FindLast(p1.Label, Symbol.Name, p1.TradeType);

                if (!String.IsNullOrEmpty(p1.Label) && ht != null)
                {
                    double cp = ht.ClosingPrice;

                    Print("Closed: Position \"{0} {1}\" closed for reason {2} with {3} profit. Entry Price {4}, Closing Price {5}, StopLoss {6}", p1.Id, p1.Label, args.Reason, String.Format("{0:$#,###.00}", p1.GrossProfit), p1.EntryPrice, cp, p1.StopLoss);

                    //Close off all open positions.
                    //Make sure to only close those positions for the current Label/Symbol. 
                    foreach (Position p in Positions.FindAll(_positionLabel, Symbol.Name))
                    {
                        ClosePositionAsync(p, (TradeResult r) =>
                        {
                            if (r.IsSuccessful)
                            {
                                Print("Closed: Closed position \"{0} {1}\".", p.Id, p.Label);
                            }
                            else if (!r.IsSuccessful)
                            {
                                Print("Closed: ### WARNING! Could not close position \"{0} {1}\"!", p.Id, p.Label);
                                Print("Closed: Error message: {0}", r.Error.Value);
                            }
                        });
                    }
                    Stop();
                    return;
                }
        }

    }
}

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