Global sensitivity analysis-how should I read this picture

I am trying to do global sensitivity analysis. In my model, I know that “phip” must be higher than 1 and “phib” must be less than zero for stability. I think the picture shows this clearly. However, I don’t understand why there are still some dots at areas, for example: phip<1 and phib<0?

thank you very much in advance,

greg.pdf (172 KB)