Django ORM using external database to unmanaged model in view says relation does not exist

I have two Postgres database connections and when using another than default ORM calls fail on views, but not raw. I am using docker and containers are connected and using Django's own runserver command. Using ORM in django command or django shell works fine, but not in a view.

As a side note, both databases are actually Django-projects, but main project is reading some data directly from another project's database using own unmanaged model.

• Python: 3.9.7
• Django: 3.2.10
• Postgres: 13.3 (main project), 12.2 (side project)

# settings
DATABASES = {
    'default': {
        'ENGINE':       'django.db.backends.postgresql',
        'USER':         'pguser',
        'PASSWORD':     'pguser',
        'NAME':         'mainproject',
        'HOST':         'project-db', # docker container
        'PORT':         '5432',
    },
    'external': {
        'ENGINE':       'django.db.backends.postgresql',
        'USER':         'pguser',
        'PASSWORD':     'pguser',
        'NAME':         'sideproject',
        'HOST':         'side-db', # docker container, attached to same network
        'PORT':         '5432',
    },
}

# My unmanaged model
class MyTestModel(models.Model):
​
    class Meta:
        # table does not exist in 'default', but it does exist in 'external'
        db_table = 'my_data_table' 
        managed = False

        # my_data_table is very simple it has id field as integer
        # and primary key (works out of the box with django)
        # it has normal fields only like IntegerField or CharField
        # But even if this model is empty then it returns normally the PK field


# My custom command in Main project
# python manage.py mycommand
# ...
def handle(self, *args, **options):

    # This works fine and data from external is populated in MyTestModel
    data = MyTestModel.objects.using('external').all()
    for x in data:
        print(x, vars(x))


# My simple view in Main project

class MyView(TemplateView):

    # But using example in views.py, random view class:
    def get(self, request, *args, **kwargs):

        # with raw works
        data = MyTestModel.objects.using('external').raw('select * from my_data_table')
        for x in data:
            print(x, vars(x))

        # This does not work
        # throws ProgrammingError: relation "my_data_table" does not exist
        data = MyTestModel.objects.using('external').all()
        for x in data:
            print(x, vars(x))

        return super().get(request, *args, **kwargs)    

So somehow runserver and views does not generate query correctly when using ORM. It cannot be a connection error, because when running command or view with ".raw()" works.

Now the funny thing is that if I change "db_table" to something what is common in both database lets say "django_content_type" ORM "filter()" and "all()" works in view too. And yes then it actually returns data from correct database. So if main project has 50 content types and side project (external) has 100 content types it actually returns those 100 content types from external.

I have tried everything, rebuilding docker, creating new tables to database directly, force reload postgres user and made sure all is owner permissions and all permissions (should be ok anyway because command side works). I even tried to use another database.

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