Testing with thralls and a horse. Both had health damage. I fired several health arrows at the ground near both of them. Inspecting the thrall, he was healing rapidly. The horse on the other hand was only healing naturally at their normal rate of about 1 health per second. The thrall was healing around 20-30 health per second.
Also, is friendly fire a thing now? I noticed that my weapon damages my thrall. Same for the horse. Before this patch, thralls would not be hurt in combat from your weapon. Now they can. Is this intentional? Or a bug?