I'm certain this isn't person mistake, since the recovery phrase was located in two different destinations: backed up within a file on S3, and printed on a piece of paper. This short article explains BIP39, the standard that defines how seed phrases are created, and summarizes how BIP32 and BIP44 https://dailybookmarkhit.com/story19207556/5-simple-techniques-for-bip39-word-list-pdf