I took the index from the words, converted the quantity to binary, included three zeros, calculated the sha256 digest, took the 1st Element of the hexadecimal to convert it to binary, additional 3 zeros on the eight digits in the binary and got 00000010011 which translates to 19 in decimal. https://bookmarkshut.com/story19682020/invalid-bip39-phrase-things-to-know-before-you-buy