Randomly picking up white with Colorpicker/colourpicker/eyedropper problem

I have used Corel Painter for many years now and have not had this issue.

I bought the 2020 upgrade and 2021 upgrade.

Now my eyedropper keeps on picking up white in random areas where there is definitely no white.

I have contacted Corel and they have been completely unhelpful - I don't even understand what they are trying to explain to me. All I know is that it is not right! There is definitely a problem.

Has anyone else experienced this problem? I'm sure I'm not alone in this.

Thank you for any answers.