Lemma wordlists in BNC

This is probably an effect of one known problem with word lists and keywords data generation. This problem occurs in the stable version only and consists in partial incompatibility of some libraries used in the stable version. Since the bugfix would be too complicated, we decided not to fix it in the current version but wait until the current 'beta' becomes the new stable version (which might be soon). Advice for you for now is to use the beta version for word lists and keyword lists operation. There is also new and (we hope) more intuitive interface for word list queries.

The 'pattern' field means the pattern that all words in a word list must match, by default it is '.*' that stands for all words -- so your procedure was right, the problem is in the system.