I am on an original iPad so I am still running the previous iOS
I further experimented and changed from date sort (which would be prefered) to title sort and now the pictures are in order as they were previously.
One drawback is that I have one album with pictures from several different sources and cameras as well as some with a title (such as from scans) rather than a frame designation. Those are no longer in the sequence taken. Date sort is very much prefered.
I have a similar problem. I used to have my photos arranged in chronological order according to the dates the photo were taken. Everythng was fine up until this morning when I installed the iPhoto update.
now when I sync my iphone, ALL of my albums in the phone contain photos arranged in the wrong order. They seem to be arranged according to the date the photos were imported or edited.
when I sync my second iphone, the same thing happened, the photos got rearranged.
I had forgotten about the recent iPhoto update.
Your observation about the dates is logical since most my my pictures go through Photoshop to be "cleaned up", sometimes more than once.
Looks like they screwed up the update so it doesn't sync on what the original frame information is or preference is checked.
I will continue to use frame name sort until Apple fixes this.