I'm trying to fix a specific element of an animation that I did without having to render the whole scene. To do that I tried putting a render region enclosing only the animation that I wanted to fix and in the compositing, I put the new animation on top of the old one and mixing them using the alpha of the render region. Unfortunately, it seems like blender sets the alpha to 0 on the outside of the render region even in the compositing step, unless I manually update the input image node after render. Since it's an animation, I can't manually update for all frames. Do you know a workaround?