Messages sent to friends not showing

I’m not sure what is the exact reason but both my messages sent to my friend and sometimes their messages tend to not show right after sending. I have to exit the app entirely and reload it for each and every message if I wish to keep the message history up to date which would like one of the two purposes of any messaging service; send messages and show them.
If it’s really a PITA to fix it I’d be happy with an in-app refresh button that just reloads conversation history.
I’m not sure about the scope of this bug, I definitely experience it in mobile app.