They also merged a potential fix to cross-instance federation syncing issues.
Issue: https://github.com/LemmyNet/lemmy/issues/3101
Referenced in the bottom of that thread is a link to the potential fix (linked by Nutomic). Here is a direct link:
https://github.com/LemmyNet/activitypub-federation-rust/pull/52
So as much as we all are focused on just the captcha, they are likely focused on getting some other things sorted out as well. The devs did mention that they were happy to get 0.18 out before reddit 3rd party apps died, so I'm pretty hopefully they will release 0.18.1 this week. They also said after 0.18 that maintenance updates wouldn't take as long.