I was drawing a Waldo panel (nothing strange there), but when it came time to add a pineapple in the background (again, nothing strange there) I was a little bit shot for time.
I made horizontal green and light green lines (he's supposed to be camouflaged in a way like Waldo), but when I noticed that this made it no longer look like a pineapple, I selected YELLOW and started to draw the vertical lines for crosshatching. Low and behold, when the yellow went over DARK GREEN the color changed to a lighter yellow. As the line progressed over the other colors, it kept the usual yellowness to it.
I know that it's pretty hard to see now.. I kept drawing. But still, this really happened. Is it a bug?