Попытка миграции в Django 1.9-странная ошибка SQL " django.децибел.а utils.OperationalError: рядом с")": синтаксическая ошибка"

Я понятия не имею, что вызывает эту ошибку. Похоже, это ошибка, для которой нет исправления. Может ли кто-нибудь сказать мне, как я могу обойти это? Это бесконечно меня расстраивает. Спасибо.

Operations to perform:
  Apply all migrations: admin, contenttypes, optilab, auth, sessions
Running migrations:
  Rendering model states... DONE
  Applying optilab.0006_auto_20160621_1640...Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "C:Python27libsite-packagesdjangocoremanagement__init__.py", line 353, in execute_from_command_line
    utility.execute()
  File "C:Python27libsite-packagesdjangocoremanagement__init__.py", line 345, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "C:Python27libsite-packagesdjangocoremanagementbase.py", line 348, in run_from_argv
    self.execute(*args, **cmd_options)
  File "C:Python27libsite-packagesdjangocoremanagementbase.py", line 399, in execute
    output = self.handle(*args, **options)
  File "C:Python27libsite-packagesdjangocoremanagementcommandsmigrate.py", line 200, in handle
    executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
  File "C:Python27libsite-packagesdjangodbmigrationsexecutor.py", line 92, in migrate
    self._migrate_all_forwards(plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "C:Python27libsite-packagesdjangodbmigrationsexecutor.py", line 121, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "C:Python27libsite-packagesdjangodbmigrationsexecutor.py", line 198, in apply_migration
    state = migration.apply(state, schema_editor)
  File "C:Python27libsite-packagesdjangodbmigrationsmigration.py", line 123, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "C:Python27libsite-packagesdjangodbmigrationsoperationsfields.py", line 121, in database_forwards
    schema_editor.remove_field(from_model, from_model._meta.get_field(self.name))
  File "C:Python27libsite-packagesdjangodbbackendssqlite3schema.py", line 247, in remove_field
    self._remake_table(model, delete_fields=[field])
  File "C:Python27libsite-packagesdjangodbbackendssqlite3schema.py", line 197, in _remake_table
    self.quote_name(model._meta.db_table),
  File "C:Python27libsite-packagesdjangodbbackendsbaseschema.py", line 110, in execute
    cursor.execute(sql, params)
  File "C:Python27libsite-packagesdjangodbbackendsutils.py", line 79, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "C:Python27libsite-packagesdjangodbbackendsutils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "C:Python27libsite-packagesdjangodbutils.py", line 95, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "C:Python27libsite-packagesdjangodbbackendsutils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "C:Python27libsite-packagesdjangodbbackendssqlite3base.py", line 323, in execute
    return Database.Cursor.execute(self, query, params)
django.db.utils.OperationalError: near ")": syntax error

вот содержание 0006_auto_20160621_1640.py

# -*- coding: utf-8 -*-

# Generated by Django 1.9.6 on 2016-06-21 22:40
from __future__ import unicode_literals

from django.db import migrations


class Migration(migrations.Migration):

    dependencies = [
        ('optilab', '0005_test'),
    ]

    operations = [
        migrations.RemoveField(
            model_name='lasersubstrate',
            name='substrate_ptr',
        ),
        migrations.RemoveField(
            model_name='waveguidesubstrate',
            name='substrate_ptr',
        ),
        migrations.DeleteModel(
            name='LaserSubstrate',
        ),
        migrations.DeleteModel(
            name='WaveguideSubstrate',
        ),
    ]

вот SQL, созданный из запуска 'python manage.py sqlmigrate optilab 0006'

BEGIN;
--
-- Remove field substrate_ptr from lasersubstrate
--
ALTER TABLE "optilab_lasersubstrate" RENAME TO "optilab_lasersubstrate__old";
CREATE TABLE "optilab_lasersubstrate" ("substrate_ptr_id" integer NOT NULL PRIMARY KEY REFERENCES "optilab_substrate" ("id"));
INSERT INTO "optilab_lasersubstrate" () SELECT  FROM "optilab_lasersubstrate__old";
DROP TABLE "optilab_lasersubstrate__old";
--
-- Remove field substrate_ptr from waveguidesubstrate
--
ALTER TABLE "optilab_waveguidesubstrate" RENAME TO "optilab_waveguidesubstrate__old";
CREATE TABLE "optilab_waveguidesubstrate" ("substrate_ptr_id" integer NOT NULL PRIMARY KEY REFERENCES "optilab_substrate" ("id"));
INSERT INTO "optilab_waveguidesubstrate" () SELECT  FROM "optilab_waveguidesubstrate__old";
DROP TABLE "optilab_waveguidesubstrate__old";
--
-- Delete model LaserSubstrate
--
DROP TABLE "optilab_lasersubstrate";
--
-- Delete model WaveguideSubstrate
--
DROP TABLE "optilab_waveguidesubstrate";

COMMIT;