Its actually possible these notes that were circulated were issued as replacement notes.
Or test notes.
The more I think about it, the more it seems unrealistic to expect any major release of Macklem-Carney $5 polymer notes. Had Mark Carney simply retired from the BoC and gone into private life, I think it wouldn't be a big deal to see his name on all issues of notes for years to come (since polymer notes should have longer life expectancies in circulation). But since he is now with the Bank of England, I think that spurred the need to get something into circulation that had the name of the actual governor, Stephen Poloz. Add to that the fact that Tiff Macklem announced his retirement a mere month following the release of the $5 note last year. That means the BoC could have a vault full of polymer $5 notes bearing the signatures of two soon-to-be-former employees, both of whom are leaving in somewhat dubious circumstances. Because the release of the polymer $5 note was moved up, it's possible that no Macklem-Poloz notes were available for publicity purposes, so some of the Macklem-Carney notes that got out of the vault ended up in circulation.
To date, there are 6 Macklem-Carney polymer $5 notes known (5 found since the November 2013 release), and their serial numbers cover a range of about 200,000. Their discoveries have not been linked to one specific geographical location.
The asking price of the note on eBay seems high, but that's only because there is still the possibility that someone could find a bunch of these notes. Perhaps a couple of years from now, $175 will be an absolute bargain.
With Tiff Macklem stepping down in May, again I must say that I find it hard to believe that the Bank of Canada will release any appreciable quantity of Macklem-Carney notes. The initial $5 notes released had prefixes HBG-HBR. Now we are seeing additional prefixes from HBS-HCB. All indications are that the BoC is moving forward, not backward.
