On some Android devices, excessive processing load may cause the screen to darken.
Turning off 'Graphics Optimization' [The cross icon on the right side of the 'play screen' > Setting > Graphics Optimization] in the App may help to resolve the issue. The App needs to be restarted for the Graphics Optimization setting to take effect.
*Keeping this setting turned off may result in slower overall App performance, therefore please turn this setting off only when experiencing display instability, and keep it on under normal circumstances.