Why are broken records created in the user database?

Question

Django

I do AJAX registration. Faced with the situation that the user jumps id users (100, 112, 113, 124), etc. User IDs that do not exist give an error 500.
First, I found an error with the csrf token, if the user reloaded the page (removed the check for the token), then there were errors when clicking (the user clicked create an account several times - put the check on an existing user). Still getting 500 errors.
What can be wrong?

@csrf_exempt
def registration(request):
    if request.POST:
        username = request.POST.get('username', '')
        email = request.POST.get('email', '')
        try:
            User.objects.get(email=email)
            json = {
                "error_login": "Такой пользователь уже существует<br>Перезагрузите страницу, возможно вы уже вошли",
                    }
            return JsonResponse(json, safe=False,)
        except User.DoesNotExist:
            password1 = request.POST.get('password1', '')
            password2 = request.POST.get('password2', '')
            if str(request.POST.get('checkox', '')) == "18": // проверка капчей на число от простых ботов
                if password1 == password2:
                    User.objects.create_user(username=username, email=email, password=password1)
                    newuser = auth.authenticate(username=username, password=password1)
                    auth.login(request, newuser)

                    # Созданием one-to-one модель Profile и привязываем её к модели User
                    current_user = request.user
                    profile_obj = Profile(user_id=current_user.id)
                    profile_obj.save()

                    json = {
                        "reload": "reload",
                            }
                    return JsonResponse(json, safe=False,)

                else:
                    json = {
                        'error_login': "пароли не совпадают",
                            }
                    return JsonResponse(json, safe=False,)
            else:
                json = {
                    'error_login': "неверная валидация поля",
                        }
            return JsonResponse(json, safe=False,)

    else:
        json = {
                'error_login': "произошла ошибка сервера",
                    }
        return JsonResponse(json, safe=False,)