I'm absolutely sure it's not person mistake, Because the recovery phrase was found in two unique places: backed up inside a file on S3, and printed over a bit of paper. This article describes BIP39, the standard that defines how seed phrases are created, and summarizes how BIP32 and BIP44 https://bookmarkilo.com/story19487124/new-step-by-step-map-for-ledger-seed-phrase-bip39