Default Half screen goes blank

Hi,

Recently my HTC One has been experiencing half blank screen issue.Screenshots are attached.
Switching between apps doesn't solve the problem neither going back and forward or home. Only after the phone is restarted screen goes back to normal and after changing wallpaper. Yes , if I change wallpaper(I use only HTC wallpapers) screen goes back to normal. Again after screen goes back normal I can bring the wallpaper I used and all is fine.
I have done clean factory restore hoping it will stop but the issue continues to appear.
Has anyone had it in they experience so far? Do you know what is the problem?
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