Yes, I just reran my notebook that used to pass all the tests and the grader and I get the same error that you show. In addition to that mismatching expected length, several of the unit tests in the notebook now fail for me.
This must be another side effect of the nltk data being changed. Here’s recent thread about similar problems in the NLP C1 W2 assignment. Mentor @Deepti_Prasad reported that other problem to the course staff, but we have not yet heard back from them.
Deepti, is it possible to add a note to your previous report suggesting that they scan all the NLP courses to see which assignments depend on imported NLTK data?