Deployment destination (heroku) fails to migrate wagtail (DjangoCMS)

We have deployed a web application developed using wagtail by referring to the page below.

Deploying a Wagtail Site on Heroku

Since I have previously deployed another app, I was able to deploy it without any problems.(to heroku-18)

So I tried to migrate, but some folders that I created in startapp were not migrated.By the way, there is no specific error message and the log seems to be fine.

makemigrations, migrate and what appears is

 Your models in app(s): 'contents', 'flex', 'footer', 'forms', 'home', 'menu_header_wagtail', 'site_settings' have changes that are not yet reflected in a migration, and so won't be applied.
  Run'manage.py makemigrations' to make new migrations, and then re-run'manage.py migrate' to apply them.

Yes, as instructed, the same thing happens over and over again.

Tried
Migrate and try a few times
Redeploying Turn off the Heroku app and deploy again
DB Delete → Migrate

I really don't know.Thank you for your cooperation.