Attempted merge results in AJAX HTTP error: Integrity constraint violation: 'tid' cannot be null

I was able to merge terms successfully using Term Merge, but then I made the mistake of attempting to confirm a merge for a term that I had already begun merging (but not confirmed) on another tab. Now no matter what I try to merge, I get the error posted below.

I was logged in as an administrator with all permissions. I've read the past issues with similar messages and a patch was released, but I am assuming that the patch has already been incorporated in the current Drupal 7 version.

An AJAX HTTP error occurred. HTTP Result Code: 500 Debugging information follows. Path: /en/batch?render=overlay&id=745&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), (:db_insert_placeholder_20, :db_insert_placeholder_21, :db_insert_placeholder_22, :db_insert_placeholder_23), (:db_insert_placeholder_24, :db_insert_placeholder_25, :db_insert_placeholder_26, :db_insert_placeholder_27), (:db_insert_placeholder_28, :db_insert_placeholder_29, :db_insert_placeholder_30, :db_insert_placeholder_31); Array ( [:db_insert_placeholder_0] => 284 [:db_insert_placeholder_1] => 525 [:db_insert_placeholder_2] => 0 [:db_insert_placeholder_3] => 1252533120 [:db_insert_placeholder_4] => 284 [:db_insert_placeholder_5] => 537 [:db_insert_placeholder_6] => 0 [:db_insert_placeholder_7] => 1252533120 [:db_insert_placeholder_8] => 284 [:db_insert_placeholder_9] => 542 [:db_insert_placeholder_10] => 0 [:db_insert_placeholder_11] => 1252533120 [:db_insert_placeholder_12] => 284 [:db_insert_placeholder_13] => [:db_insert_placeholder_14] => 0 [:db_insert_placeholder_15] => 1252533120 [:db_insert_placeholder_16] => 284 [:db_insert_placeholder_17] => 48 [:db_insert_placeholder_18] => 0 [:db_insert_placeholder_19] => 1252533120 [:db_insert_placeholder_20] => 284 [:db_insert_placeholder_21] => 513 [:db_insert_placeholder_22] => 0 [:db_insert_placeholder_23] => 1252533120 [:db_insert_placeholder_24] => 284 [:db_insert_placeholder_25] => 519 [:db_insert_placeholder_26] => 0 [:db_insert_placeholder_27] => 1252533120 [:db_insert_placeholder_28] => 284 [:db_insert_placeholder_29] => 514 [:db_insert_placeholder_30] => 0 [:db_insert_placeholder_31] => 1252533120 ) in taxonomy_build_node_index() (line 1970 of /home/justasso/public_html/drupal/modules/taxonomy/taxonomy.module).