I took the index from the words, converted the number to binary, added a few zeros, calculated the sha256 digest, took the main Portion of the hexadecimal to convert it to binary, added three zeros to your 8 digits in the binary and acquired 00000010011 which translates to 19 in https://social40.com/story4359745/ledger-seed-phrase-bip39-no-further-a-mystery