Current version on Haystack (2.10) combined with Elasticsearch produces weird results when you want to sort search results on charfield, the issue has been reported here https://github.com/toastdriven/django-haystack/issues/866 and here: https://github.com/toastdriven/django-haystack/issues/569
Long story short, to fix the problem you need to set indexed=False and stored=True on CharFields that you want to use for sorting.
You should also set indexed=False on BooleanFields (if there are any in the search index model). Here's an example how the correct module would look like:
class BlogIndex(indexes.SearchIndex, indexes.Indexable): title = indexes.CharField(model_attr='title') sorted_name = indexes.CharField(model_attr='title', indexed=False, stored=True) text = indexes.CharField(document=True, use_template=True) active = indexes.BooleanField(model_attr='active', indexed=False) < ... >
As you see above, we have created two fields for model_attr='title', first is regular, called title, the second one is sorted_name that is used for sorts. We also set Boolean 'active' as non-indexed, however it'll work for your search filters, it just won't get tokenized (yep, strange, but fact).