Nexus 7 Pixelated Screen Using 4.12.5

Hi, I’m working using UE4 4.12.5.
I know this was resolved from 4.12.5. but I still experience pixelated screen only in Nexus7 with MobileHDR.
I tried to turn HDR off then screen is fine. but if I turn HDR on then screen is pixelated except UI widgets.
Why this problem happen to me? Please help me. :frowning: