Factory Boy Iterator generates the wrong order

Question

I use Iterator to create a strict sequence of values.

    class MyModelFactory(DjangoModelFactory):
        class Meta:
        model = MyModel
        django_get_or_create = ("first_field",)

        first_field = Iterator(["value_1", "value_2", "value_3", "value_4"])
        second_field = Iterator("aaaa", "bbbb", "cccc"])
        third_field = Iterator([1, 2, 3, 4])

I expect that result should be next:

---

    [
      ("value_1", "aaaa", 1),
      ("value_2", "bbbb", 2),
      ("value_3", "cccc", 3),
      ("value_4", "aaaa", 4)
    ]

But the outcome is unpredictable:

    [
      ("value_1", "aaaa", 4),
      ("value_2", "bbbb", 3),
      ("value_3", "cccc", 1),
      ("value_4", "aaaa", 2)
    ]

And when I use this MyModelFactory as a RelatedFactory two times in row, my database raise an error duplicate key value violates unique constraint third_field. Yes third_field must be unique. The question is why does this error occur if I use django_get_or_create?

Any ideas?