arrows of healing are fine when it comes to players but when i shoot it at other mobs like wolves and cows, they clearly do damage.
edit: on stronger mobs like creepers, they seem to take longer to kill with healing arrows so i think the issue may be that it hits like an arrow at first but then heals a percentage of the damage
It deals normal arrow damage based on speed and then instantly applies healing effect. Cows for example can't survive the fully charged shots, so the healing effect, which comes after can't take place. When the arrow is really slow, the effect overweights it, so you can heal 3 health per shot. Try it 🙂