can you tell me what model of phone this is, please?
Ok, I'm still a bit confused on the timeline over which this occurred and also on which phone.
If I understand correctly, Person A upgraded from an older iPhone (#1) to a newer one (#2). In the process of this update, Person B received a message on their phone (#3) indicating that Person B and phone #3 would also receive texts sent to Person A's phone. Then the text in question showed up on phone #3 about 3 days later, and was an earlier message from Person C and dated several weeks prior?