Core ML MLOneHotEncoder Error Post-Update: "unknown category String"

Apple Developer community,

I recently updated Xcode and Core ML from version 13.0.1 to 14.1.2 and am facing an issue with the MLOneHotEncoder in my Core ML classifier. The same code and data that worked fine in the previous version now throw an error during predictions. The error message is:

MLOneHotEncoder: unknown category String [TERM] expected one of

This seems to suggest that the MLOneHotEncoder is not handling unknown strings, as it did in the previous version. Here's a brief overview of my situation:

• Core ML Model: The model is a classifier that uses MLOneHotEncoder for processing categorical data.
• Data: The same dataset is used for training and predictions, which worked fine before the update.
• Error Context: The error occurs at the prediction stage, not during training.

I have checked for data consistency and confirmed that the dataset is the same as used with the previous version.

Here are my questions:

1. Has there been a change in how MLOneHotEncoder handles unknown categories in Core ML version 14.1.2?
2. Are there any recommended practices for handling unknown string categories with MLOneHotEncoder in the updated Core ML version?
3. Is there a need to modify the model training code or data preprocessing steps to accommodate changes in the new Core ML version?

I would appreciate any insights or suggestions on how to resolve this issue. If additional information is needed, I am happy to provide it.

Thank you for your assistance!