Examine the SQL statement that extracts COLUMN information from Teradata.
Copy this SQL statement and run outside of the script directly against Teradata for one of the tables in question.
If you are getting zero rows back then that is why COLUMN entries are not found.
Examine the SQL statement to determine why no COLUMNs are being extracted for the table(s) in question.
Modify the SQL statement as needed to return COLUMN records.