Sorry, can't help with a fix. But can confirm it not right on your system. On my CS6, the pen/lasso trace line changes depending on the underlying color. Actually, it looks to me like it varies from white to black and shades of gray in between depending on underlying luminosity. If I trace on a color whose luminosity is close to 50% mid tone, the trace line looks like middle gray and is often hard to see.
My only suggestion is to try the age old tip or resetting Photoshop preferences. If that does not work, try turning off your GPU (Edit/preferences/performance). Maybe Photoshop does not like your particular video card.