I think this is a Chrome bug. I can't reproduce it in FF or IE. In Chrome, it also only happens on the main ACP index page and not in all cases. I can reproduce it here but not on my test forum.
It's not related to inherit -- the color is just being ignored, even with !important. The text decoration is being applied though, so the CSS isn't being skipped. I'm not sure if we can boil this down to a consistent test case though (to report to them).