My brother and I live in the same home, but unfortunately we cannot play in the Online together. For some weird reason, only 1 of us can actually see chat being actively used or type and see our message in chat show up. The other person cannot see chat being updated or see the friend request or invite from the other person in the home.
What is really weird, is when the person that can see the chat active and chat regularly, when he logs out of the game, then within a few moments, the other person in the home can see the chat update and start to type and see their own chat show up.
This tells me this may be a backend server issue, as we have never seen anything like this, yet can play multiplayer / co-op just fine in every other similar game, such as Wolcen, Grim Dawn, POE, etc.