I have downloaded and checked the TableBank dataset from your dataset homepage
I have found some issues in the annotations, the README denotes the number of tables in the Table Detection task as follows:
| Task |
Word |
Latex |
Word+Latex |
| Table detection |
163,417 |
253,817 |
417,234 |
But I ran my script to check the data annotations, it showed that there were only 101889 tables in the Word subset.