I have an iPhone 4 with FW 4.3.3. Lately when I switch the mute button it doesn't give me the vibration feedback as usual. But when I switch back in to ring mode it suddenly does. When the phone is in locked it does the exact opposite, it vibrates when I mute it and doesn't when I unmute it - that's how I want it. But the reaction is not consistent. Anyone else have this? BTW vibration alert is set to be on in both cases. I find it super annoying, since I want the vibration feedback only when I switch into silent mode like it did until recently. I'm just talking about the feedback here, the phone does what it should in the respective modes.