I have a Sony Xperia Z3 running cm14, that has served me well over the years, but recently it's acting a bit weird. At first it would restart when I dropped it, I blamed it on the battery getting out of place, since the back glass is broken and a part of the battery is exposed. Yesterday though, the phone started restarting randomly, even when I have it on a solid surface, just watching a YouTube video, not even touching it. It works great while charging, while for some reason it will super charge after 50%, (it takes about an hour and a half to reach 50%, while it takes less than 10 minutes from there to reach 100%) this started happening from yesterday as well. The battery is relatively new, i have changed it less than a year ago.
I also tried to calibrate the battery, but it didnt help at all.
No new apps installed or settings changed.