The vocab lesson Step 13 of Kanji Kentei 10級 is listed in the study center as having 14 terms, but the actual terms list and quiz for the lesson only have 12 terms.
Found some more. Under Kanji Kentei 6級 vocab lessons, step 2 is listed as 13 terms but there are only 12 in the terms list, and step 3 is listed as 24 terms but there are only 21 in the terms list.