Hello,
It is fresh project with tonemapper enabled in config like here
https://docs.unrealengine.com/latest/images/Platforms/Mobile/PostProcessEffects/TM_INI_Location.png
Another person tested it on the same device with same OS and saw same bug.
I am also using codeworks version like in this doc https://docs.unrealengine.com/latest/INT/Platforms/Android/GettingStarted/1/