Foreignkey field does not load in list_filter properly

[AyanNandaGoswami]

class ProductSubcategory(ModelMixin):
category = models.ForeignKey(ProductCategory, on_delete=models.CASCADE, verbose_name=('Category'),
related_name='subcategories')
name = models.CharField(max_length=100, unique=True, primary_key=False, verbose_name=('Subcategory name'))
thumbnail = models.ImageField(upload_to=get_subcategory_thumbnail_upload_path, verbose_name=('Thumbnail'))
cover_image = models.ImageField(upload_to=get_subcategory_coverimage_upload_path, verbose_name=('Cover image'))
sort_order = models.IntegerField(default=0)

@admin.register(ProductSubcategory)
class ProductSubcategoryAdmin(ModelMixinAdmin):
list_display = ('uuid', 'category_name', 'name', 'status', 'sort_order')
list_filter = ModelMixinAdmin.list_filter + ('category', )
raw_id_fields = ModelMixinAdmin.raw_id_fields + ('category', )

I set category to list filter but it does not load in admin panel as filter.
But when I use django default admin then it works properly.
Please help