beta 2 AJAX error: column 'tid' cannot be null

Just update to beta 2,

trying to merge 2 terms, I receive the following error:

Si è verificato un errore HTTP in AJAX. Codice HTTP di risposta: 500 Di seguito le informazioni di debug. Percorso: /batch?id=106&op=do StatusText: Service unavailable (with message) ResponseText: PDOException: SQLSTATE[23000]: Integrity constraint violation: 1048 Column 'tid' cannot be null: INSERT INTO {taxonomy_index} (nid, tid, sticky, created) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2, :db_insert_placeholder_3), (:db_insert_placeholder_4, :db_insert_placeholder_5, :db_insert_placeholder_6, :db_insert_placeholder_7), (:db_insert_placeholder_8, :db_insert_placeholder_9, :db_insert_placeholder_10, :db_insert_placeholder_11), (:db_insert_placeholder_12, :db_insert_placeholder_13, :db_insert_placeholder_14, :db_insert_placeholder_15), (:db_insert_placeholder_16, :db_insert_placeholder_17, :db_insert_placeholder_18, :db_insert_placeholder_19); Array ( [:db_insert_placeholder_0] => 23 [:db_insert_placeholder_1] => 70 [:db_insert_placeholder_2] => 0 [:db_insert_placeholder_3] => 1322680828 [:db_insert_placeholder_4] => 23 [:db_insert_placeholder_5] => [:db_insert_placeholder_6] => 0 [:db_insert_placeholder_7] => 1322680828 [:db_insert_placeholder_8] => 23 [:db_insert_placeholder_9] => 72 [:db_insert_placeholder_10] => 0 [:db_insert_placeholder_11] => 1322680828 [:db_insert_placeholder_12] => 23 [:db_insert_placeholder_13] => 73 [:db_insert_placeholder_14] => 0 [:db_insert_placeholder_15] => 1322680828 [:db_insert_placeholder_16] => 23 [:db_insert_placeholder_17] => 74 [:db_insert_placeholder_18] => 0 [:db_insert_placeholder_19] => 1322680828 ) in taxonomy_field_update() (linea 1771 di /var/www/my-site.com/modules/taxonomy/taxonomy.module).

Nodes associated to old term are not merged to the new one, but only decoupled from old term

Thank you for resolving this