Pattern Screen Lock Issue regarding S3

I recently purchased the S3 for TMO. I have been having a recurring problem with my S3 regarding its screen lock. The pattern screen lock that I have enabled seems to shift location from the center screen to the side of the screen. It has happened already twice, having to reset the device twice. I took a screencap so you can see exactly what I am referring to. https://www.dropbox.com/s/siwmans2pv39yo1/Screenshot_2012-06-23-22-53-10.png Any advice or ways to fix it (other than having to reset the phone)? Thanks!