on_delete=CASCADE doesn't fire pre_delete and post_delete signals

tortoise-orm==0.19.3

Setup

class FileBaseModel(models.Model):
    host = fields.ForeignKeyField(
        "models.Equipment", related_name="files", on_delete=fields.CASCADE, null=True
    )

@pre_delete(FileBaseModel)
async def equipment_media_pre_delete(
    sender: Type[FileBaseModel],
    file: FileBaseModel,
    using_db: Optional[BaseDBAsyncClient],
) -> None:
    log.info(f"pre_delete signal for file {file}")

Code

equipment = await Equipment.create(...)

file = await FileBaseModel.create(host=equipment)
await file.delete()
#### INFO:     pre_delete signal for file <FileBaseModel>

file = await FileBaseModel.create(host=equipment)
await equipment.delete()
#### Nothing happens! No logs...

Start by reproducing the shown FileBaseModel and Equipment setup, comparing file.delete() with equipment.delete(). Trace the deletion cascade and signal dispatch from those delete entry points. Done means cascading deletion invokes both pre_delete and post_delete for the related FileBaseModel, with regression coverage for the example.