I've not seen that with mine so you have two options:
1. It could be a defect, call or stop in a V store and see if you can get it changed out
2. It could be a crappy app. I had an app installed to tell me how many phone calls/VM's, TXTs, ect I had on the home screen (not the pull down alert screen) and never used the phone without it. I kept having the freaking text messaging app (the native app in Android) crash constantly. I got extremely fed up and when someone else said to uninstall things, that's exactly what I did.
Typically if it's an APP, it's something that has phone call permissions if that's what is screwing up. I know it's a pain, but uninstall EVERY app, because some have odd permissions that they probably shouldn't have. If you want, make a list of them all, and if the problem doesn't recreate itself, reinstall them one at a time and see if that helps. Hoping for good luck for you bc that's freaking annoying :\