When inside the chat itself, there is no notification sound for incoming messages. The messages just show visually, with no audio.
But when outside of the chat, or not in the messages app, the sounds occur when messages come in.
This was the case on multiple Samsung phones, and with multiple different messages apps for SMS/MMS/RCS.
Is there a way to solve this? Couldn’t find any solutions after researching
Use case example: You’re busy doing something, but you send a message to someone and leave the chat open because you can’t close it at that second. You look away from your phone and continue what you were doing. A message comes through but because the chat is open, you don’t hear a sound. Then you get back to your phone 30 minutes later, and find that the person had already replied to you 27 minutes ago. If the sound still played even while the chat was open, you would have stopped what you were doing and responded to them as soon as you got their message.
Sounds like you missed out on a booty call.
For what it’s worth 4 days later, this bugs me too on my Google Pixel phone! My daughter texts me something, we go back and forth, something interrupts and I don’t realize she’s asked a question and I’ve left her hanging.