iPhone 5 restarts when opening texts

I bought an iPhone 5 on launch day and that same day, my phone restarted itself when opening a text directly from the lock screen. I didn't think much of it then and just went on with it but then within the next three weeks, it happened to my phone three more times. I figured Apple would have me restore my phone before swapping it out for me so I went ahead and did that on my own, before calling Apple's tech support about the issue.

My phone seemed to be working fine, after doing the restore, but then the next day, it did the same restart thing twice, when trying to open texts. So that was six times that it happened to me within a month so I finally called Apple and they told me I'd done everything they would've recommended I do so they went ahead and set up a Genius Bar appointment for me to get it replaced.

The next day, I get my phone replaced by Apple and everything seemed to be working ok after the first few days... But then exactly one week after getting it replaced, it happens again! I've now had the replacement phone for 10 days and it has happened to me three more times.

I've tried searching forums about this issue but haven't found anything so I thought I'd share it with you all, in case any of you have heard anything about this or if it's happened to any of your phones.

And by the way, I originally set up both phones as new phones, when I got them so I know it isn't an issue with an iCloud restore.