`AutoModel.xx` classes from hf's transformers do not work otherwise, and an error because the metadata is `None` here: https:/huggingface/transformers/blob/main/src/transformers/modeling_utils.py#L518-L522

That said, I only have very basic knowledge of this so might be wrong here. I personally had to re-save the model files with metadata added for them to work with `AutoModel...` classes.