Generative extend for ProRes 4444 alpha clips?

Can generative extend support clips with alpha transparency?

I tried generative extend on my video clip which is ProRes 4444 with alpha and it baked in a black background instead of preserving transparency.

This particular setup is a green screen talking head shot where my workflow is to render out the ultra-key clip to a ProRes 4444 file which I import back into the project.

This allows me to bake-in the ultra-key and other effects, while preserving the ability to switch out the background layer which is underneath.

I know this isn't first-world priority, but would have been nice to be able to use generative extend and preserve the transparency so this would still work.