Contacts/Text Msg issue

[nthnu]

For some reason, one of my contact's name doesn't appear anymore in the stock Text Messaging app, just their number. When I get a message from that person, the white envelope icon says "Message from Firstname Lastname". But that contact in my Contacts list (through gmail) has it as just "Firstname". Not sure what the deal was. I backed up all my texts, and deleted them all. Then I got a new message, and the same issue happened. I only use my gmail contacts, and no other apps or services. Any ideas? Thanks