Hibernate ORM 5.4.12.Final Bug with NULLS_LAST, NULLS_FIRST sorting

I want add sort to pageable request to db postgres. I want add rule for null ordering.
For this I use

        Sort.Order order = new Sort.Order(ASC, "sortString", Sort.NullHandling.NULLS_LAST);
        val pageable = PageRequest.of(0, 100, Sort.by(order));

But when I look to SQL request

order by sortentity0_.sort_string asc limit

I don’t find nulls last.
but when I add property

order_by.default_null_ordering: last

this works correctly.

Tell me, is this normal behavior?