LastPass, 1password and bitwarden are happily filling out both fields with the same generated password without preventing new password generation. Seems like a solved problem.
They happily try. But there are so many poorly coded websites they can't handle all possibilities. This seems like a useful feature, although I prefer the way 1password solves it.
(They handle multiple accounts on the same site, so their UI is a list rather than a single item. "Generate a random password" is just a special list item, so they can show you both.)
(They handle multiple accounts on the same site, so their UI is a list rather than a single item. "Generate a random password" is just a special list item, so they can show you both.)