OK I will try and explain this as best I can. About 3 hours ago "not saying this is when it started, just when I noticed" I noticed that when my phone was locked it will light up and show me that I have a facebook notification, but there is absolutely no sound at. Now this is not limited to just my phone being locked its just not playing the notification at all. This has just happened today. I have checked the sound notification setting and it is on and my phone is not on silent. Now what makes it weird is I have 2 friends on facebook that say with their IPhone they are now noticing the same thing since I have said something and they are both on the same carrier as I am "Verizon". I have another friend on AT&T with same IPhone as the rest of us and everything is working the way its supposed to work. To add to my confusion my wife has an Android with Verizon same as me and her push notification sounds are working just found. So are there any other IPhone 4S users out there, on Verizon network, using 5.1.1 software having this problem all of a sudden?