Here's a tip from iMore's Ally Kazmucha for users who are suffering from disappearing or improperly syncing iCloud contacts once they've upgraded to iOS 7.1.2.
It turns out the issue isn't with iCloud, it's with a new default in iOS 7.1.2. The update causes your iOS device to switch your contacts back to the On My iPhone group. To fix the issue, simply switch your contacts group back to iCloud in settings.
1. Go to the Settings app.
2. Go to Mail, Contacts, Calendars, and scroll to the bottom.
3. Select Contacts.
4. Click on Default Account.
5. Finally, select "iCloud" instead of "On my iPhone."
Kazmucha has also written up a tutorial on how to weed out disappearing contacts from your phone. To read that head over to iMore.