Me and my friend were solving permutation question on leetcode and we came up with this below answer

func permute(nums []int) [][]int {
    
    if len(nums) == 1 {
        return [][]int{nums}
    }

    var result [][]int

    for i, num := range nums {

        tempans := permute(append(nums[:i], nums[i+1:]...))
        for _, perm := range tempans {
            result = append(result, append([]int{num}, perm...))
        }
    }
    
    return result
}

the above function returns wrong answer

[[1,2,3],[1,3,3],[3,3,3],[3,3,3],[3,3,3],[3,3,3]]

But the code worked when we replaced permute(append(nums[:i], nums[i+1:]...)) with

remaining := append([]int{}, nums[:i]...)
remaining = append(remaining, nums[i+1:]...)

below is the final working code

func permute(nums []int) [][]int {
    if len(nums) == 1 {
        return [][]int{nums}
    }

    var result [][]int

    for i, num := range nums {

        remaining := append([]int{}, nums[:i]...)
        remaining = append(remaining, nums[i+1:]...)

        tempans := permute(remaining)
        for _, perm := range tempans {
            result = append(result, append([]int{num}, perm...))
        }
    }
    return result
}

why what is the difference?