Unable to save Canada supplier sites with valid 6 character postal codes

When users enter a supplier site for a Canada supplier, they enter a valid correct 6 character postal code (e.g. M5E 1E6) but they cannot save the record.  Turns out this is caused by the fact that the file we receive from Vertex which is loaded into our Geographical Hierarchy only contains the first 3 characters of the Canada postal code (i.e. M5E).  Confirmed that HZ: Address Validation Level for Application profile was already set to Warning for Payables application.  The Geography Validation for Country to "Warning" in the Trading Community Geographical Hierarchy.  Is there some additional setting we need