gradient backgrounds work in ie8 but not ie9
I'm using the PIE2 beta, it and is working beautifully with ie8. All of the CSS3 decorations work.
I'm using the -pie-background rule for a lot of gradient backgrounds. All of these backgrounds render just fine on ie8. However, in ie9, all of the CSS3 decorations are rendered EXCEPT the gradient backgrounds. Image backgrounds work just fine.
I tried removing my IE stylesheet for ie9 (and with it PIE), and it looks the same, suggesting ie9 may not be using (or needing) pie at all.
But putting it back gives the same result. My IE-only rule does include ie9:
<!--[if lt IE 10]>
<link rel="stylesheet" type="text/css" href="_assets/ie.css" />
An example of one of my -pie-background rules:
-pie-background: linear-gradient(to bottom, #CCCCCC 0%, #FFFFFF 100%);
Are both on the server. Any ideas what might be wrong?