THE 5-SECOND TRICK FOR BIP39

instead of an outright rejection leads me to think a sentence with no matching checksum can however be used (whichIt can be essential which the mnemonic sentences are produced from randomly picked quantities! These quantities is often produced in a variety of various ways, which might be explained in other posts here, like "What exactly is an RNG"

Entropy is a complicated element. Your mnemonic could be insecure if this element is employed improperly. Go through additionalSituation (a) is useful When you have a mnemonic sentence that has an invalid checksum and you would like to use it with a wallet that not only checks the CS, but also refuses to use your entropy Until it's Bip-39 compliant