Actually, that's not really wrong. Assuming at this point the wallet was already created and saved in encrypted form, it's totally legit Armory ask again the password to unlock it if the password was already discarded from memory. I suppose the on-demand "make backup" option will have to ask for the password anyway if done at a later time.
This is a regression. Old armory (python wallets) did not have you submit the password to generate the backup after creation. The password does live in memory for the whole wizard lifetime, just as before, but decryption happens in the cppbridge now.
New Armory unlocks via a callback process: encrypted assets list their encryption key id, the code tries to resolve that. If it finds no key, it prompts the caller for candidates. I can force feed the passphrase by hijacking the prompt, I was just lazy to.