[Python / YOLOv8] なんだこのエラーは(オリジナルモデルに追加学習させようとしたら怒られた)

from ultralytics import YOLO

# Load a model
model = YOLO('myyolov8.yaml')  # build a new model from YAML
model = YOLO('./runs/detect/train3/weights/last.pt')  # load a pretrained model (recommended for training)

# Train the model
results = model.train(data='mycoco.yaml', epochs=100)
results = model('test.jpg')

File "C:\Users\～略～\venv\main.py", line 11, in <module>
    results = model.train(data='mycoco.yaml', epochs=100)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\～略～\venv\Lib\site-packages\ultralytics\engine\model.py", line 654, in train
    self.trainer.train()
  File "C:\Users\～略～\venv\Lib\site-packages\ultralytics\engine\trainer.py", line 208, in train
    self._do_train(world_size)
  File "C:\Users\～略～\venv\Lib\site-packages\ultralytics\engine\trainer.py", line 424, in _do_train
    self.metrics, self.fitness = self.validate()
                                 ^^^^^^^^^^^^^^^
  File "C:\Users\～略～\venv\Lib\site-packages\ultralytics\engine\trainer.py", line 546, in validate
    metrics = self.validator(self)
              ^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\～略～\venv\Lib\site-packages\torch\utils\_contextlib.py", line 115, in decorate_context
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\～略～\venv\Lib\site-packages\ultralytics\engine\validator.py", line 195, in __call__
    stats = self.get_stats()
            ^^^^^^^^^^^^^^^^
  File "C:\Users\～略～\venv\Lib\site-packages\ultralytics\models\yolo\detect\val.py", line 168, in get_stats
    stats = {k: torch.cat(v, 0).cpu().numpy() for k, v in self.stats.items()}  # to numpy
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\～略～\venv\Lib\site-packages\ultralytics\models\yolo\detect\val.py", line 168, in <dictcomp>
    stats = {k: torch.cat(v, 0).cpu().numpy() for k, v in self.stats.items()}  # to numpy
                ^^^^^^^^^^^^^^^
RuntimeError: torch.cat(): expected a non-empty list of Tensors

from ultralytics import YOLO

# Load a model
model = YOLO('path/to/last.pt')  # load a partially trained model

# Resume training
results = model.train(resume=True)