Anyone else seeing a new very odd native messages issue?

Ok this is weird. In the last day or so suddenly half of my messages new or old are no longer showing me the contact details. Just the number they called from. So for example Had a message last week still in my messages app from John, Now john is showing as 071234567. Equally, if I go into the message it shows as locked and says share your name and photo and gives you the option to add the number to a new or existing contact. All very strange as I've done nothing to alter anything.