Default [Q] Spontaneous Random Bricking?

So about a month ago I rooted my d800 and put CloudyStock on it. Everything was fine until a couple hours ago when I notice the LG symbol on the screen like it's restarting. I figured I had just held down power button or something but got distracted and wasn't too worried about it. Phone was probably 70% charged. An hour or so later I go to turn it on and it's totally dead. I charge it and it doesn't react to the charger at all, no lights, no charging indicator, nothing. I tried a different charger.. same thing. It's just totally bricked out of absolutely nowhere. I haven't been messing with it or anything at all since back a month ago. When the LG symbol came on I was just carrying from one room into another and hadn't been doing anything on it. I tried plugging into my computer to try some recovery magic and my computer doesn't even recognize anything is connected.

So, assuming it doesn't magically come to life in the morning, I'm guessing my only option is to pay the deductible and get it replaced. I'm just kinda confused why/how this would happen totally spontaneously. Has anyone heard of any history of something like this? Thanks!