I’ve just started a new job, and having not set up a new laptop in over four years, I’ve gotten a little rusty. So, if like me you use mac’s Terminal.app and haven’t changed it in well, ever, then you might find some issues on a new Sierra machine, particularly if you use the combo of zsh/oh-my-zsh and the agnoster theme like I do.
So tl;dr - turns out if you install oh-my-zsh, switch it to the agnoster theme, add a patched powerline font, and add a solarized terminal profile the colours are still wrong, and it’s because the solarized main repo hasn’t been updated post-Yosemite.
The issue is referenced in this pull request and the file in question can be found here.
Download that file and import it into Terminal and bam! You’re set.