Around 5am this morning I awoke to a slight burning smell, and discovered that my Z5 premium was extremely hot. I am not talking the slight warmth issues from the processor (as discussed in my forums). I am talking so hot that I actually placed the phone outside my house because I was worried it might catch on fire. I've had the handset for many months and never noticed any issue previously. It was not connected to a charger at the time, and not doing anything out of the ordinary.
The handset was not powered up, it was completely unresponsive.
I had no choice but to leave it outside and go back to bed. It has since recovered from the episode (I'm using it now).
Most probably that was an app acting app, maybe stuck in the background consuming a huge amount of resources.
As your phone is working fine now, you may just forget about it and continue using it normally. But if you want to be sure this may not happen in the near future, I'd suggest that your backup using Xperia Companion (all important data except settings and apps) then perform a software repair using Xperia Companion. This will do a clean installation of the latest firmware and will also wipe your internal memory. Follow the steps given in the blue link, do not connect your phone until prompted to press volume down while plugging USB cable.
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