For words that have only 3 letters, there isn't a 4th letter. For example with the word “add”, there are no more letters afterwards and so need to be the word "incorporate". The word “addict” is inside the BIP39 wordlist however, you might have applied “addi” for “addict”. You might https://social-galaxy.com/story4945156/how-much-you-need-to-expect-you-ll-pay-for-a-good-bip39-seed-phrase-mnemonics-generator