This has randomly started happening since I "Cleaned up" my contacts. Fundamentally, my contacts are now based on Exchange, instead of phone, and most of the time this is fine, but from time to time, in messages, numbers appear, instead of names, for some people. If i create a new message, I can choose the contact and it'll show the name, but when I press send, it will file it under the persons thread, but still no name showing. Even if i click on the number, it shows "Open Contact", and if I click call, it'll shows the persons picture, so it knows this number belongs to a contact, but refuses to display the name or picture. Annoyingly, it only happens to the people I contact most often too.