I took the index of your words, converted the amount to binary, included three zeros, calculated the sha256 digest, took the 1st Component of the hexadecimal to convert it to binary, extra three zeros towards the 8 digits in the binary and acquired 00000010011 which translates to 19 in decimal. https://livebackpage.com/story4364777/fascination-about-invalid-bip39-phrase