When using two databases in tests, django applies migrations to both

Question

I have two databases: "default" and "logs". "logs" is MongoDB which is used for logging.

Here are my settings:

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql_psycopg2',
        'NAME': 'project',
        'HOST': 'localhost',
        'PORT': 5432,
        'PASSWORD': 'passwd',
        'USER': 'user',
    },
    "logs": {
        "NAME": "djongo",
        "ENGINE": "djongo",
        'HOST': 'localhost',
        'PORT': 27017,
        "USER": "user",
        "PASSWORD": "passwd",
    },
}

I also wrote a router

class LogsRouter:

    route_app_labels = {"logging_system"}

    def db_for_read(self, model, **hints):
        """
        Attempts to read auth and contenttypes models go to auth_db.
        """
        if model._meta.app_label in self.route_app_labels:
            return "logs"
        return None

    def db_for_write(self, model, **hints):
        """
        Attempts to write auth and contenttypes models go to auth_db.
        """
        if model._meta.app_label in self.route_app_labels:
            return "logs"
        return None

    def allow_relation(self, obj1, obj2, **hints):
        """
        Allow relations if a model in the auth or contenttypes apps is
        involved.
        """
        if (
            obj1._meta.app_label in self.route_app_labels
            or obj2._meta.app_label in self.route_app_labels
        ):
            return True
        return None

    def allow_migrate(self, db, app_label, model_name=None, **hints):
        """
        Make sure the auth and contenttypes apps only appear in the
        'auth_db' database.
        """
        if app_label in self.route_app_labels:
            return db == "logs"
        return None

In the test I added two databases:

class TestTestCase(TransactionTestCase):
    databases = ["default", "logs"]

When starting I get the error:

djongo.exceptions.SQLDecodeError: 

    Keyword: None
    Sub SQL: None
    FAILED SQL: ('UPDATE "django_celery_results_taskresult" SET "date_created" = "django_celery_results_taskresult"."date_done"',)
    Params: ((),)
    Version: 1.3.6

But why is the "django_celery_results_taskresult" migration trying to apply to MongoDB, since I have written in the router that only models from the logging_system application should work with MongoDB?

What am I doing wrong?