Anyone has this problem with your contact. Let's say:
1) You received a call from a person not in your People (Contact) list
2) When call ended, on the "Phone" page, you press the "+" button to save this number as new contact.
3) The call entry in "Phone" now shows the person name with his phone number
4) When you go to All Apps->People, the newly saved contact is NOT shown in the People list.

Very weird problem!!