No result when app_lable in uppercase

[felixdevelop]

When I use symbols in uppercase:

$ ./manage.py rebuild_index   # OK

WARNING: This will irreparably remove EVERYTHING from your search index in connection 'default'.
Your choices after this are to restore from backups or rebuild via the `rebuild_index` command.
Are you sure you wish to continue? [y/N] y
Removing all documents from your index because you said so.
All documents removed.
Indexing 294 films

$ ./manage.py shell

>>> from haystack.query import SearchQuerySet
>>> len(SearchQuerySet().all())
0

When I rename app (without rebuild_index):

$ ./manage.py shell

>>> from haystack.query import SearchQuerySet
>>> len(SearchQuerySet().all())
294

Current Environment:

Virtualenv/Python 3.5

Django 1.9
Xapian 1.4.1
Xapian-Haystack 2.1.1
Django-Haystack 2.6.1

[claudep]

rebuild_index is a django-haystack command. What makes you think this is specifically related to the xapian backend?