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I have iphoto and an ipad.
before the latest updates iphoto had them newest on top but the ipad had them newest on bottom. the order was correct otherwise
then the updates flipped this back but the photos were out of order. like newer ones were above older ones
removing the photos from the ipad and readding them didn't change this
deleting the photos from the album and reimporting them as duplicates didn't help
I then changed the sort order to be by filename and synced it was correct on the ipad that way.
but then changing the sort back to by date it wouldn't change the sort order again. it was stuck as by filename
with the photos sorted by name in iphoto I unchecked the album in itunes and synced so the photos were removed, and then readded it and synced them back on (only ~100 photos so it went quick)
interetingly it put them on by filename sort order this time.
so the problem it definently in ios. it's holding onto bad sort data somehow