Lack of background-color in gradients.

For some cases like IE9 (non-compat mode) where you can only have one filter applied at a time or any time a gradient filter is set as disabled (enabled=false) the background color is non-existent or gray.
There should be a valid approximation/fallback for these cases.
Ok.  So I found where you're setting the color of the elements like label in .label-variant.
In the current BS3 default components, this will not repo.  It's only in the downstream case where someone else may leverage #gradient on it's own that this will show up, or in my case I found where our code is overriding the label color downstream but the gradient takes precedence where it's 100% supported.