Book Ch 1 - IMDB-based review classifier not detecting obviously negative reviews


I was experimenting with the Chapter 1 Notebook on Colab and I’m getting some strange behaviour from the movie review classifier in the “Deep Learning Is Not Just for Image Classification” section.

It categorizes many obviously negative reviews as positive:

Screenshot 2023-07-31 at 22.58.04
Screenshot 2023-07-31 at 22.58.26

I’m confused. Is it known to do that?

I understand that the accuracy is not 100% but these seem like low hanging fruit to get right.

Am I missing something?