Call Screen Frozen - Return or Software Bug?

Once every 5 or 6 calls my screen freezes up saying "call ending" or "calling". When this happens I can back out of the phone call app but once I click on the phone call app it is still frozen, exactly as it was. The only way to make it go away is to power my phone on and off.

I know there are some bugs with iO4 but is this problem something worth returning my phone or is this a bug that will be fixed with an update?

 

Thank you. That's what I thought but haven't seen it reported.