In the first screen, I am very happy that the person now receives an explanation that their login this time is a one-shot deal. Previously, it could be (and was to me, months ago) confusing that they were logged in once, and thereafter would have problems trying to do it because they didn't create a password (and had no idea how to create one).
In the second screen, I think the language is better but I still have two concerns:
(1) Does clicking on "join" proceed to require them to create a password, as it does now? I still don't like that, especially if simply replying to the email (rather than clicking on anything) gets them right into the group, at least as an email subscriber. I am hoping that clicking on "join" makes them an email subscriber (just as replying to the email does), and THEN goes on to give them the OPTION to create a password - rather than making creation of a password (if they don't already have one) a requirement as it is now.
(2) Does simply replying to the email automatically enroll them as an email subscriber, as it does now? If so, I think that should continue to be explicitly stated (as it used to be).