My point was one does not need to keep the Master Public key saved as they can find the keys when they try all three seeds one by one and each time they will get each Master Key. Then combine the master key and seed to recover the wallet. For a 2 of 3 wallet, two set is enough.
Half the point of a multi-sig is to have redundancy in the set up. A 2-of-3 wallet allows you to lose one seed phrase and still be able to recover your wallet, provided you have all three master public keys. If you don't save the master public keys, then you
need all three seed phrases in order to recover the wallet, even if the wallet itself is 2-of-3.