Black Screen IOS3

Since my wife updated her watch to IOS3 twice now while getting a message her phone vibrates and she glances down to see a black screen. Let's say out of 15 messages it's happened twice. This time before a hard boot I checked her iPhone and it was still connected to Bluetooth. It requires a hard reset to recover and all is good. I'm guessing a bug in IOS 3 as no problems till she updated. Anybody else having this issue?

 

We called Apple but they haven't seen one yet. Hoping it's ios3 bug as no problem till update. They did suggest a erase and restore if it happens again. Then if still a problem, replacement.