that is not as it should be, so pardon my very basic questions - just to be sure:
How do you sync from iTunes? Have you set the "Sync Photos from" pop-up menu in the "Devices" tab in iTunes to "Aperture" and not to your "Pictures" folder?
To sync the edited versions, you have to sync with Aperture and not with the masters folder on the Disk. Set Aperture to share Previews with the iLife Applications (in the Aperture Preferences > Previews tab) and to automatically create the Previews. Set the preview quality and size to your main display dimensions.
If you already have that, please post back and explain more how you are syncing with your iPhone.
I checked these settings and they are as you asked them to be.
However; I noticed that the issue does not occur on other devices I have. The only difference: I'm registered as iOS develop and one of my devices has iOS6 on it and that's the one that fails. So it seems to be a bug in combination with iOS6.
Thanks for your support!
If you you have build previews, and if you are syncing from Aperture and not a folder in the Finder, then you may be having a problem with the current Preview bug. Aperture does not always create the previews after editing with certain plug-ins or using an external editor.
Does your problem apply to all images you are syncing, or only to images with certain kinds of edits? Are your originals jpegs? And what is the size of the images?