Hi Civo,
let me try to understand, you:

fine tuned a model with 4 classes. That worked fine
you’ve added another 4 classes, fine tuned again, the model works but with very low accuracy
on-device the model is not recognizing any of the new classes.

Did I get it right?
some suggestions:

by your results, it seems that the quality of the data used for training the additional 4 classes is worse than the original 4. Maybe you might need to look into that with more data for example
since the accuracy is low, Task Library might have a default scoreThreshold that is too high for the new classes and so it’s filtering out them during inference.