Was the release uploaded to pypi or a download page? If so, that's released IMHO. eg, debian, various news outlets, and others auto scan download pages for new releases.
And if we catch a minor packaging error at this point, it's easy enough to fix on the spot without having to do an entire new release.
Except in this case somebody got really eager, saw the release process starting, and posted a link to our downloads page (and I'm not entirely certain if it would have been possible to get the incorrect package from it), rather than waiting for and linking to the release announcement once we'd vetted and made everything public.
Will wait for the official release announcement next time. Sorry again.
Mistakes can be made if you have to do version number tweaks in various places before releasing.