Lack of notification for text messages when phone has been idle for a given time.
My problem is I am not getting text message notifications instantly when sent if phone has been idle. If using the phone or it has been opened just recently, I will receive them ok. I have checked with another phone and have found out that the time the message was sent is the same time that shows on my phone when checking time on message but may be delayed in notifying me with a sound or vibration anywhere from 5 to 15 minutes so far, I have noticed. I have checked my settings and gone through them more than a few times to make sure nothing is keeping it from notifying me instantly along with AT&T troubleshooting my issue on the phone with him seeing my exact complaint as he text me and called me back 30 minutes later and we tried this again with phone being idle the entire time and no notification until you open phone up. He said all was working correct on your end and suggested I go into a store which I have done, and they also went through all the settings and suggested maybe it was just the phone itself but not sure. Of course, he texted my phone while there, but it had not been idle and received the message instantly. When it does this and you check the time sent from other phones mine always matches the exact time but if I happen to not open the phone, I will not know it for a good while. If I just happen to open the phone for whatever reason, then it will notify me and when I check the message it may say sent 10 minutes ago but I had no idea. This is the U318AA that you AT&T sent me because my other phone was not going to work after 2/2022. It just looks like to me it is something to do with sleep, snooze, or doze mode that is keeping it from alerting until you open the phone then it delivers them. Seems if it was network related it would not have the exact times the messages were sent showing on my end. Is there something I am missing or overlooking here? I mainly noticed this using this phone for work purposes where I need to get a text immediately when sent due two of us working together doing instrumentation calibrations. I thought maybe it was just this phone but when looking online there seems to be a lot having this issue with Samsung's newer iPhones and such. Any help or fix for this issue?