Incorrect rotation in Aperture slideshows

Have you set Aperture to render Previews for your images? If not, I'd try to update the previews for the images in the slideshow.

I found, that Aperture showed the images in the slideshow correctly in the right orientation, if high-quality previews wee available, while displaying the slideshow:

From Aperture's main menu bar: Photos > Update Previews.

This still feels like a bug to me as surely the slideshow should run from a version, not from the orientation of the original??

Sure, the slideshow should show the edited version, but to reender the version Aperture needs access to the originals or up-to-date previews of the current version.