Peg 27 has had very good feedback on fit, however anomalies do sometimes occur in production on random shoes. Quality control at the factory is set up to catch these rare cases but every once in a while you'll have one slip by the goalie. You may have unknowingly bought one of these.
This is likely an inconvenience for you, but can you go back to the store that sold you the shoes to try on another pair of Peg 27's in the same size? It would be interesting to find out if another pair fit the same as your "short" pair or it they do fit true to size.
Have you tried to exchange them?