iPhone automatically calls my Voicemail

Hey there,

I am using my unlocked 4S with T-mobile. I have a permanent voice message on there that never goes away.

Anyway, I noticed that if I turn off my phone and turn it back on again, it automatically dials my voicemail number.

Does anyone else see this too? Is this a bug or a feature? lol

Before there is any speculation.... No it's not jailbroken

Edit: On a side note... looks like they havent updated the shutdown icon (the circle thing in the center of the screen when you turn it off) to the new high res image for the retina display (it's pixelated)... Looks like Apple software engineers are overlooking the fine details