The following code attempts to solve Combination Sum (Reuse Allowed). Identify the line containing the subtle bug that causes incorrect results or inefficiency:

The following code attempts to solve Combination Sum (Reuse Allowed). Identify the line containing the subtle bug that causes incorrect results or inefficiency:

def combinationSum(candidates, target):
    candidates.sort()
    result = []
    def backtrack(index, path, target):
        if target == 0:
            result.append(path[:])
            return
        if index == len(candidates) or target < 0:
            return
        max_use = target // candidates[index]
        for count in range(max_use + 1):
            path += [candidates[index]] * count
            backtrack(index + 1, path, target - candidates[index] * count)
            # Missing path restoration here
    backtrack(0, [], target)
    return result