Bleached iphone screen [on hold]

I noticed this behavior of Iphone display and I would like to ask you if your Iphone does the same, and what is the cause. When I watch dark video on Iphone, and immediately press home button to switch to bright homescreen, interesting thing happens. All the pixels are "bleached" and after few seconds they retain their original colors. I would like to know if this is software or hardware "thing", since it does not happen when I switch from dark picture to bright homescreen. Could it be that by running dark CPU-consuming apps like videos, the OS is slow to adapt to high brightnes, and "forgets" to turn down voltage to the screen? (like an eye going from dark to bright place) Please try it yourself, ( record short dark video, and then press homebutton to get to the bright homescreen) and tell me if you know the cause.

Edit: it's not inherent "software" bug, because when I printscreen the bleached screen, the colours are as they should be, so it's probably that OS forgets to lower the voltage to the screeen or (---)?