Here is an example where during printing process the plates had too much ink or the ink was too wet for the one application, most noticeable on the bust of Laurier.  You can see that the words Bank of Canada and the coat of arms were also affected.  Also note the reddish line drawn through the bust of Laurier.  This is a cancellation mark used to mark sheets to be rejected.  The same cancellation mark is also on this note.