While the host environment is not mean for actual safety application with overlaid screens as such, it can be used for demonstrating the QSR in the host environment. The planned target is a system with certified RTOS as instructed in the white paper etc.
But in the host environment demos the screen flickering may happen because there is not yet default double buffering available. It is available in the target reference implementation.
Maybe the double buffering could be added to the host implementation as well to ensure flicker-free demonstrations. The flickering might happen especially when drawing larger bitmaps. It does not seem to appear with smaller bitmaps so often. Or it is not spotted so easily.