many to many through table not recognisable in custom migration

[Mayank Jain]

I have a model A having field b as many to many. I wanted to make b default through table's default id field to be UUID.
If I do that using through table, the admin interface changes to Inline and I don't want that. So, I tried writing a custom migration to do that.

If I am checking the default intermediate table using apps.get_model it exists but when I use the same table in migrations it gives me error:

File "./manage.py", line 19, in <module>
    execute_from_command_line(sys.argv)
  File "/Users/mj/.virtualenvs/proj/lib/python3.6/site-packages/django/core/management/__init__.py", line 371, in execute_from_command_line
    utility.execute()
  File "/Users/mj/.virtualenvs/
proj/lib/python3.6/site-packages/django/core/management/__init__.py", line 365, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Users/mj/.virtualenvs/proj/lib/python3.6/site-packages/django/core/management/base.py", line 288, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/Users/mj/.virtualenvs/proj/lib/python3.6/site-packages/django/core/management/base.py", line 335, in execute
    output = self.handle(*args, **options)
  File "/Users/mj/.virtualenvs/proj/lib/python3.6/site-packages/django/core/management/commands/migrate.py", line 200, in handle
    fake_initial=fake_initial,
  File "/Users/mj/.virtualenvs/proj/lib/python3.6/site-packages/django/db/migrations/executor.py", line 117, in migrate
    state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "/Users/mj/.virtualenvs/proj/lib/python3.6/site-packages/django/db/migrations/executor.py", line 147, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "/Users/mj/.virtualenvs/proj/lib/python3.6/site-packages/django/db/migrations/executor.py", line 244, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/Users/mj/.virtualenvs/proj/lib/python3.6/site-packages/django/db/migrations/migration.py", line 112, in apply
    operation.state_forwards(self.app_label, project_state)
  File "/Users/mj/.virtualenvs/proj/lib/python3.6/site-packages/django/db/migrations/operations/fields.py", line 70, in state_forwards
    state.models[app_label, self.model_name_lower].fields.append((self.name, field))
KeyError: ('app', 'A_b')