With bloom enabled it is a lot easier to see this issue happen, but it's not required.
Some block types and colours when looked at directly with the star at your back will make it appear discoloured.
{F7066, size = full}
I made a ship that has all the colours and types: {F7065}
Make sure the plate is perpendicular with the nearby star, and that you look at the plate from the star's viewpoint.