Bearing in mind that the Board has plenty of references from your previous employers you need to be careful here. Be confident, but also be honest. Just pick on a few issues to start with and see if the discussion goes any deeper. There may be a reason for the Board to be checking something out that a previous employer of yours has said about you. This could be either positive or negative.

Alternatively it could just be a conventional and routine question. It is best to be prepared and perhaps check with your referees before attending the Selection Board.