EXPECTED RESULT: When the Certificate activity is configured to "Certificate Type" = "Letter Embedded" or "Letter Non-Embedded", the PDF downloaded by the user should be in the US Letter size, 8.5 by 11 inches (215.9 mm x 279.4 mm).
ACTUAL RESULT: The PDF downloaded by the user is A4 (ISO 216) size, 8.3 by 11.7 inches (210 mm × 297 mm)
STEPS TO REPRODUCE:
1) Install the mod_certificate
2) Create a course, enrol a test user and add a Certificate activity
3) Choose "Certificate Type" = "Letter Embedded" or "Letter Non-Embedded"
4) Use the test user to download the Certificate
5) Open in a reader and look at document properties "Page size".