When I receive a notification bar, at the top of my screen, informing me of a new message, I many times slide that down, to send a quick reply there, rather than fully opening the messenger app.
CONSISTENTLY, the app DOESNT SEND THE MESSAGE.
Seriously, I have lost count of the number of times when I only realized that my replies were actually never sent HOURS after I typed them.
cocamojoe82 about Messenger, v128.0