Leetcode 40 - combination sum 2- practice with a bug - need to fix the duplicate items in the output

Leetcode40_combinationSum2_practice.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Leetcode40_CombinationSum
{
    class Leetcode40_CombinationSum
    {
        /* Need to design the algorithm to fix the bug:
         * 
        Input:
        [10,1,2,7,6,1,5]
        8
        Output:
        [[1,1,6],[1,2,5],[1,7],[1,2,5],[1,7],[2,6]]
        Expected:
        [[1,1,6],[1,2,5],[1,7],[2,6]]
        */
        
        static void Main(string[] args)
        {
        }

        public IList<IList<int>> CombinationSum2(int[] numbers, int target)
        {
            var subsets = new List<IList<int>>();
            var subset = new List<int>();

            Array.Sort(numbers); 
            bool[] visited = new bool[numbers.Length];

            findSubsetWithSumByUniqueNumbers(subsets, subset, numbers, target, 0, visited);

            return subsets;
        }

        /// <summary>
        /// using recursive function to conduct depth first search
        /// </summary>
        /// <param name="allSubsets"></param>
        /// <param name="subset"></param>
        /// <param name="numbers"></param>
        /// <param name="remaining"></param>
        /// <param name="start"></param>
        private void findSubsetWithSumByUniqueNumbers(
            IList<IList<int>> allSubsets,
            IList<int> subset,
            int[] numbers,
            int remaining,
            int start, 
            bool[] visited)
        {
            // boundary check - sum value
            if (remaining < 0)
            {
                return;
            }

            // base case 
            if (remaining == 0)
            {
                allSubsets.Add(subset);
                return;
            }

            int length = numbers.Length; 

            // depth first search using recusive function 
            // Each number in C may only be used once in the combination.
            for (int i = start; i < length; i++)
            {
                var visit = numbers[i];
                var current = i;                               

                var newList = new List<int>(subset);
                newList.Add(visit);

                var nextUsed = new bool[length];
                Array.Copy(visited, nextUsed, length);
                nextUsed[i] = true;

                var target = remaining - visit;
                var nextStart = current + 1; // number can only be used once

                findSubsetWithSumByUniqueNumbers(allSubsets, newList, numbers, target, nextStart, nextUsed);
            }
        }
    }
}

Need to design the algorithm to fix the bug:

    Input:
    [10,1,2,7,6,1,5]
    8
    Output:
    [[1,1,6],[1,2,5],[1,7],[1,2,5],[1,7],[2,6]]
    Expected:
    [[1,1,6],[1,2,5],[1,7],[2,6]]

Need to remove duplicate item [1, 2, 5] and [1,7].