I too, am convinced this is a software issue. It began just after UCUFNJ5 was pushed out OTA in August. Up to that time the phone has worked well since it's purchase in November of 2013. There is absolutely no rhyme or reason for when the error happens. I did note that on one Saturday when I was home and connected to wifi, the error happened and would not go away. I left the house to go to the store and while out itr began working again. IWhen I got home it immediately popped the error, but I also noticed it was downloading updates at the time. I turned off wifi for the rest of the weekend and the phone was fine. I will typically go up to 2 weeks without incident. Usually it requires one reboot and it's fine again. The time I just described it was not. It also was flakey as hell last weekend. Friday afternoon it wigged out and would not come back with a reboot. I had to power down and pull the battery, and I did reseat the SIM and put it all back together and it was fine that night. Saturday it was wiggy for a time, and Sunday evening it forced a reboot once. It's annoying as hell. Phone is stock. I rooted it after this began in August and have shut down a lot of apps using Titanium. I run Nova Prime, but nothing fancy. I rooted primarily to remove crapware and have some control over the device. I'm tossing out this information in the hopes it might help someone figure out what is happening. It does not behave like any hardware issue I've ever seen and I can say for a fact that during at least one of it's bad episodes it was trying to update something...