Build command is not localizing dates

When I view the pages through page preview they have localized dates, but the same doesn't happen when I build them. These are the relevant configurations:

```python
LANGUAGE_CODE = 'pt-br'
LANGUAGES = (('pt-br', 'Brazilian Portuguese'),)
TIME_ZONE = 'America/Sao_Paulo'
USE_I18N = True
USE_L10N = True
```