This is not a new issue after a number of samsung phones.
To be clear this is my issue....
I get notifications on new messages but NOT on further messages in a thread...whatever that means.
As an example if I get a new message it alerts. If I respond to that message, and then the person responds back, I dont get an alert.
It appears this is the case until after some unknown time period when it alerts again.
I have spoken to Samsung a few years back and they said there was no solution but I wondered if that had changed?
Unlike the apparent test crew that live looking at their phone (sarcasm)... I don't. I put my phone down and continue working only to miss the responses that someone may send.
Not sure what the time algorithm is?
If others are having the alert issue this may be what you are referring to. Ive done everything suggested that I can find but most only address the overall alert issue and no other solution to this specific point.
Would love some advice if someone knows how to fix this if I'm missing something.
At least there should be an option to turn it on or off.
What carrier are you using?
Try setting an error report through the Samsung Members app.
Trying google messages will just confirm that it's a software issue with Samsung Messages app
Does SMS or MMS too?