This is $1,000 in face value of provincial notes being redeemed every year for the last four years. Even if these were all the most common and least valuable notes in this category (1920 Dominion of Newfoundland treasury notes), we're still talking ~$1M in collector value.
Could the Bank of Canada simply be buying these up for the National Currency Collection and writing the liabilities off the books? Spending that kind of cash would be a big story all its own.