Why are my Events in iOS 8 iPhoto in a completely random order?
It's a bug.
No fix at all right now.

I've tried all the usual suspects, re-order in iPhoto, delete &amp; re-add all my Events, clear &amp; re-sync everything.

Events arrive in random order whatever I do… a different random order after each of the attempts to fix.

There's been a lot of discussion on the Apple community site about it, no-one's found a fix, the bug is known to have been reported already.