I have a stylesheet that works as expected in Mathematica 8. It does not work as expected in Mathematica 9.
In the stylesheet I have set FontColor to RGBColor[0.501961, 0, 0] for ItemParagraph. DisplayFormula and InlineFormula have FontColor set to Automatic (I've also tried Inherited).
When I press ctrl+( to start a formula from within an ItemParagraph the color is the same as for my Text cell (black). The FontColor option for Text is Automatic.
Interesting behavior. When I type esc+intt+esc the font color is RGBColor[0.501961, 0, 0] and it creates an inline formula region (or is it displayformula?). When I type ctrl+/ it creates an inline formula region but the color is black.
I have both Mathematica 8 and Mathematica 9 installed and the behavior does not exist on Mathematica 8.