Foreign Key Columns does not exist

Describe the bug
A clear and concise description of what the bug is.
So I've been working with a pretty complicated system. We use a custom sanic wrapper and tortoise for our models, the catch is we don't run migrations, EVER!. We manually write SQL for our tables and just write a similar models based on it in python.

Recently I encountered this bug and don't have any idea how should I go about solving it. So I have a user_roles models which looks similar to this where the app column FK references a master app table which contains a name column as the source_field. Similarly it is done on the role column as well.

The problem is these source_field="name" does not exist as per the ORM when I'm trying to query. The field does exist as when I query the master App or roles table, I get the data.

The user_roles table also fetched the username from the user table correctly but does not in this case.

Why is this behaviour happening ? Is it because I've also added a Foreign Key constraint on the DB level ?

I've tried changing versions and cleaning up database and loading up new data but nothing seems to work here.

Also as the user_roles Table on the DB contains data, when I switch to a TextField() for these two everything starts working great.

    username = fields.ForeignKeyField(
        "{}.{}".format(CONFIG.config.get("NAME"), "User"),
        related_name="roles",
        on_delete=fields.CASCADE,
        source_field="username",
        pk=True,
    )
    app = fields.ForeignKeyField("{}}".format(CONFIG.config.get("NAME"), "Application"), related_name="app", source_field="name")
    role = fields.ForeignKeyField("{}.{}".format(CONFIG.config.get("NAME"), "Role"), related_name="role", source_field="name")
    # app = CustomTextField(index=True)
    # role = CustomTextField(index=True)
    enabled = fields.BooleanField(default=True, null=False)
    permission = fields.TextField(null=True)

This is the actual error I got.

To Reproduce
I have a complicated setup so won't be able to share a correct way but I've described the error as clearly as possible

Expected behavior

Normally I would expect this to work as any normal FK would.

The report names no repository files or tests and does not provide a reproducible setup. Start by reducing the user_roles ForeignKeyField definitions for Application and Role against a manually created schema, then check how source_field="name" is resolved; done means producing a minimal reproduction or confirming the expected behavior with a regression test.