Try clearing your browser cache. I have buff and green because that's what my boards colors are.
Colored Coordinates in VC game
I don't have that bug, so it's a local problem. Try reinstalling windows or clear cache like Martin said.
I just got it again but now they're blue, and it's on a different game this time.

I also had orange a couple days after I first posted this, but didn't get a screenshot.
Reloading the page a single time fixes it.
So any time I go to this VC game the coordinates on the board are... green and white?
On any of my other VC games, it looks like this: