In UMG, is animation of alpha possible with a material?

I have an Image in UMG that alphas in and out over time using the animation timeline. When I apply a texture to the image, it fades in and out as expected. However, if I swap the texture for a material (I’d like it to have an additive blend mode) the animation fade is lost and instead it just pops in and out at full opacity. I’ve even tried nesting my image in a Border and changing the alpha on that, but didn’t have any luck.

Is this an issue with how I’ve set up my material? Or can I simply not animate the opacity of a material within the UMG animation timeline?