Xara Gradient Problem or Illusion?

I noticed a blue tint in a gradient with no blue in it. The blue area is 20% black.
Is this a color error or just the way our eyes work?

I suspect that it's the way the light grey and red interact. Although it does seem a little bizarre.

Wow!

It's an illusion. I just checked it with color picker. That area is gray but it looks blue. Very interesting illusion :-)

The white background could be adding to the illusion.

I just went over it with Pixie. There's no blue there. Spooky!