I'm not sure what's going on with my Evo, but all of a sudden it's been deciding to put itself in silent mode for no apparent reason and I'm missing tons of calls because of it. I will turn the sound back on and then all of a sudden it's off after a couple of hours for no apparent reason. I don't want to have to return the phone, but I'm not sure what other options I have at this point. Has anyone heard of this issue?