(See figure)

I sometimes see regions in my model that are colored grey in the contour legend. I am not able to identify these regions. I tried to change the limits for the legend, yet the grey thing keeps coming.

Another interesting thing : The grey part comes only in animation. When I analyse the frames separately, it isnt there.

Does anyone have an idea what it could mean? And how do I go about changing it so that the maximum computed values appear red instead of grey?

Thank you for your time in reading this!