Is this some sort of weird feature I'm unaware of? I'm using the 4S (w/factory iOS5). Whether I'm on the home screen or in an app, the volume will all of a sudden turn up to full blast. It happens sporadically, I can't replicate it every time but it happens probably every second or third time I use the phone. The volume icon will appear on the screen, and when I try to turn it down it goes back up on it's own. Has anyone else experienced this? I've owned every single iPhone and never had this issue before. Is this an OS issue or do you think it's my phone that's defective (or is it some weird iOS5 feature).