Yeah, I'm not sure how long it was broken. Slack's support for public instances seems a bit strange. Even the new invite code is only good for 2000 new members

Yeah, I'm not sure how long it was broken. Slack's support for public instances seems a bit strange. Even the new invite code is only good for 2000 new members or something, after which that link will again redirect to the page that requires a @google.com address until someone notices.