It’s not just New Brunswick and it’s not just marriage records. Records like these are created by clerks given information by others. Census records, too. My mother hated her first name. My paternal grandmother hated her first name. Neither of them can be found in public records using their birth first names. My paternal grandmother’s headstone does not have her birth first name. Let’s not forget the ‘helpful’ immigration officers who, in the 19th and 20th centuries, anglicized names so they coul be pronounced in the US.
Bottom line: verify everything! Don’t trust a source unless you can verify it. Oh, and it’s not just names. A paternal great great grandfather rarely gave the same answer as to his date of birth to census takers.
WikiTree help has given similar advice about sources and which kind are more likely to be reliable. Linda is right. Explain what you’ve done. Others may not change what you’ve done if you’re lucky, but do you really want to send them down a rabbit hole?