I took the index on the words, converted the number to binary, added 3 zeros, calculated the sha256 digest, took the main A part of the hexadecimal to transform it to binary, additional 3 zeros towards the 8 digits of the binary and obtained 00000010011 which translates to 19 in https://bookmarkmoz.com/story18843836/the-invalid-bip39-phrase-diaries