3 Dots Stuck (iMessage)

Just bought a new iPhone 15 and after some syncing, noticed the 3 dots appear next to my ex’s name as if he is typing something to me. Ironically, I had just deleted a message that he never responded to and that’s when I noticed the 3 dots, so I assumed he was responding at that moment. However, after syncing messages and turning phone off, the 3 dots will not disappear unless I open the chat box and close back out. Then the 3 dots appear again after entering messages app.

is it possible I missed a message during my iPhone setup?

How do I get this unstuck?