Just curious about this - two users, both on iOS26 - we each have backgrounds set for the chat yet we can't see the others I am on DEV Beta, other person is on PUB Beta. Would that be the issue? Seems odd if that's the case.
After using a background with my husband , I looked on our messages on his iPad and it doesn't seem to be showing for him. Will look at his phone when he's back. His devices are UTD .
EDIT : It syncs between users but it took two days to do so with my husband. The first thing he asked me was how to turn it off on his phone 😂