Printing errors make stamps more valuable. Here is a 1977 12c definitive, from the Rick Penko collection, with the country name a denomination shifted downwards.

Canada #713 Never Hinged 1977 12c QEII Shifted Impression

Canada #713 Never Hinged 1977 12c QEII Shifted Impression
Lot 64 in our auction Saturday 21st August 2021
#shiftedimpression #canadastamps #penko