Hi, @Carissa! It's hard to say what's going on without a little more info. However, I do think that bubbles tend to show up more in white icing as a general rule, especially when white icing is laid on dark cookie. What white food coloring are you using? And what if you don't use white food coloring - do you still get bubbles in the icing without the coloring?
But . . . I can't see how the coloring itself would affect the bubbling, other than that, in stirring in the coloring, you may be incorporating too much air. To minimize the incorporation of air when using any color of coloring, I always add the coloring when the icing is stiff and stir in the water very gently. If you add coloring to a loose icing and/or stir too vigorously, you'll kick up more air bubbles in the icing.