I know this is a very old thread, but Sony did have software problems back in 2016. Back then I had a Xperia Z3+, and it had problems focusing. I had it repaired by my local repair center, and they got it working again. It stopped working the next day, so I tried factory resetting the phone. Viola, the camera was working, but it lasted only a few hours. I probably factory resetted that thing five times, just to get the camera working. I then dropped the phone and broke the digitizer, rendering the phone useless, but that's besides the point.
