I am new to Django but have some experience with MVC web development.
I am encountered with a weird problem, hopefully, it is only weird to me, not all folks.

After doing some changes (changing attribute’s names) in models project_name/models.py. I ran: python manage.py makemigrations to migrate the DB with new changes. But it showed that “No changes.”

So I decided to do a fresh re-migrate DB 🙁

1. Delete DB and recreate empty DB
2. Delete migrations/ folder and recreate folder with __init__.py
3. Re-run makemigrations

OK. Now the weird thing happens.
No matter how I change in models.py, the migrations/0001_initial.py file always keep generate old attribute.

# models.py
class Task(models.Model):
    STATUS_CHOICES = [
        ('PENDING', 'Pending'),
        ('PROCESSING', 'Processing'),
        ('COMPLETED', 'Completed'),
        ('FAILED', 'Failed'),
    ]

    pdf_file = models.FileField(upload_to='pdfs/')
    status = models.CharField(max_length=10, choices=STATUS_CHOICES, default='PENDING')
    
    #Previously `preview_url`
    preview_img = models.ImageField(blank=True, null=True, upload_to='previews/')

    #Previously `thumbnail_url`
    thumbnail_img = models.ImageField(blank=True, null=True, upload_to='thumbnails/')

    error_message = models.TextField(blank=True, null=True)
    uploaded_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    def __str__(self):
        return f"Task: {self.id} - {self.status}: {self.pdf_file.name}"

# migrations/0001_initial.py
...
    operations = [
        migrations.CreateModel(
            name='Task',
            fields=[
                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
                ('pdf_file', models.FileField(upload_to='uploads/')),
                ('status', models.CharField(choices=[('PENDING', 'Pending'), ('PROCESSING', 'Processing'), ('COMPLETED', 'Completed'), ('FAILED', 'Failed')], default='PENDING', max_length=10)),
                ('preview_url', models.URLField(blank=True, null=True)),   # WEIRD
                ('thumbnail_url', models.URLField(blank=True, null=True)), # WEIRD
                ('error_message', models.TextField(blank=True, null=True)),
                ('uploaded_at', models.DateTimeField(auto_now_add=True)),
                ('updated_at', models.DateTimeField(auto_now=True)),
            ],
        ),
...

Why? and How to fix this?
Thanks in advance.