IPhoto causes portrait format images to sort incorrectly in iOS

Question

After importing photos into an Event in iPhoto, then on quitting iPhoto, the portrait format photos within that Event have their modification date/time changed from the creation date/time (which is what it should be) to the date/time that the photo was imported into iPhoto.  This causes the Photos App under iOS 6.0.1 and above to sort the photos within that Event so that all the landscape format images are displayed ahead of all the portrait format images.  This is because the iOS Photos App incorrectly sorts on modification date/time rather than creation date/time.
Steps to Reproduce: Take a number of photos with a camera that records orientation information in the EXIF data (e.g. Nikon DSLR or similar).  Ensure there is a mixed assortment of both landscape and portrait format photos.  Import those photos into an Event in iPhoto (with Sort by Date selected).  You will see in iPhoto that the images are sorted correctly in chronological order.  Examine the Info (CMD-I) on both types of image, and you will see that modification date/time is the same as creation date/time for every image (as it should be).  Now quit iPhoto, and relaunch it.  In iPhoto, look again at photo Info (CMD-I) of photos in that Event, and you will see that all of the portrait format images have now had their modification date/time changed to the date/time of import into the iPhoto library.  Using iTunes, sync that Event with an iOS device (e.g. iPad).  On the iOS device, look at the Event in the Photos App, and you will see it is sorted incorrectly, with all the landscape images first, followed by all the portrait images.

Answer 1

Sigh.  I know I'm being troll bait, and I really don't believe you can be so obtuse, but I'll have one last stab, just in case you're genuine.
Point 1.  Nothing on your Mac needs iPhoto.  Every application on your Mac can deal with photos as files, without intervention or advice from iPhoto.  Even the Finder gets it right, orienting the images correctly from EXIF information.  Even Quicklook gets it right.  You can remove iPhoto from your Mac and everything will continue to display images correctly.  There is no need for iPhoto to change mod date in the EXIF data on a photograph inside the iPhoto library, simply because the camera was oriented vertically instead of horizontally when the picture was taken.  It helps no-one and the only thing affected, adversely, is the Photos App on iOS.
Point 2.  If it were really the warped intention of iPhoto developers that vertically oriented photos should be considered to have been modified when they were imported into the iPhoto library, then iPhoto should treat them the same as it treats other photos modified in iPhoto.  It should put a copy of the original file, as modified, into the Modified section of its library, and it should leave the original in the Originals section.  And it should offer a 'Revert to Original' option.  It does not do that for these vertical images.  There is no copy in the Modified part of the library.  And 'Revert to Original' is greyed out, unobtainable.
Point 3.  It is only in the past 5 or 6 months that iPhoto began clobbering the modification date of vertical images.  For the previous 9 years that I've been using iPhoto and the 18,000 images in my iPhoto library, everything had been fine.  Only the vertically oriented photos imported into iPhoto since version 9.3.2 have had their mod date trashed.  This is a pernicious and no doubt unintentional bug, that fortunately impacts nothing else on the Mac (and assists nothing else either).  It does affect the Photos App on iOS.  It might affect the iPhoto App on iOS too.  I don't know, as I don't have it.
Point 4.  The iOS Photos App is also incorrect in sorting on mod date instead of creation date.  This began with iOS 6.0.1.  I have also submitted a bug report to Apple on that issue.