I performed a Hard Reset, enabled the Device Lock and set it for 24hrs. Made a call and pulled the phone away from my face to see if I could reproduce the same effect to alleviate a software conflict and sure enough while in call when I pulled the phone away from my face the dial pad dissapeared and I was back at the home screen. Sent an email into HTC to see if they where aware of this or could test it themselves and possibly offer a fix.
Seems some of our GSM brothers over at XDA having the same issue as well
http://forum.xda-developers.com/show...69#post4563769