Since Apple wants to avoid carrier SMS issues, charges and more, you see the bumps in the road.
Usually I receive text messages from certain people with their name since I have them in my contact list. But once in a while a message thread is started from their icloud account. Even if I had just been messaging with their phone number minutes before. Others have told me the same happens sometimes from my number as well. There seems to be no rhyme or reason why this starts and stops. It is annoying because a separate thread is started on the same conversation and sometimes I don't even recognize their icloud address. What is going on here?