Hi,
I had the same problem, but I discovered that the issue is not with "Wrong Color", it has to do with the type of the curve being copied.
Look at my example below, I created a red bulls-eye (hollow inside) and tried to copy the color from the blue square - corel closed the it !
But if I add the blue color as a style - it will work.
WHY ? I DO NOT KNOW !!!
I am sure it is a bug in both X6 Update 4 & in X7 update 4