Who I have the same questioned this topic

In Verizon messenger app when I receive a message I can open that message to get the Message info / details. Here's my question - messages from the same person will usually show they were sent to me, but sometimes it switches and shows it was sent to me AND to the person that sent it. So I looked on my husband's phone and messages from my phone do the same thing. Why does it switch back and forth like that? And why do the details show my phone sometimes sending text messages to itself? (note - I don't actually receive a text message from myself, just the details on the message show that it was sent to both numbers).