I had the same issue with mine. It even got to the point where my bionic would have constant reboots. I had never rooted my phone, and everything was stock version 5.5.886. I simply didn't want to void any warranties. At first I thought it might be an app, so I restored my system (try that first when you can). But the system still kept restarting. So, then I contacted Verizon, they asked if I had the Standard Dock and/or the Car Navigation Dock. I said yes I do. They notified to me that there is a glitch in those products that are causing random restarts and that there will be a fix this month that should resolve it. I said ok.
However, I have a business account with Verizon and can't have these random restarts when talking with customers and clients. What ended up happening is that when I text or view facebook, the screen would lock up then proceed to do the reboot process with the dual core logo. I then went straight to an official Verizon store in my area and had the technician there view my issue. And of course, I'm thinking in my head that the phone will work perfect for him.... But it didn't thankfully! He noticed the massive lag on the phone and then placed an order for a replacement bionic for me.
I'm 2 days into my new bionic and so far so good. (Knock on wood). I seriously think I had a received a bad bionic out of the box with some hardware issues that caused the restarts. But do try to restore your system and don't install any apps for 24 - 48 hours. If you notice the restarts right away, then you know you have some issues related to hardware or preinstalled software. Take it into your local verizon store and have them view the issue and process your replacement phone. Trying to diagnose it over the phone with Verizon tech support won't work too well since they follow a linear procedure and may not be able to issue out a new phone. Have a technician physically look at the issue.
Hope that helps Michelle.
Thanks, Seiga. I'll take it in. I don't use the car or navigation dock, but do have dozens of apps installed, including Facebook. The strangest thing is it reboots when I'm not doing anything. Very random.
Regardless, looks like Verizon knows there's a hardware issue so hopefully they'll honor a replacement.