This behavior is intentional, iirc. Endermen cannot be hit by projectiles, regardless of whether they are aggro'd or what the source of the projectile is.
EDIT: Does it actually deaggro, or just get lost in caves or something?
Dinnerbone, will this behavior be present in all mobs eventually ( getting wet and reduced invisibility effectiveness ), or will it always be unique to wolves?
This behavior is intentional, iirc. Endermen cannot be hit by projectiles, regardless of whether they are aggro'd or what the source of the projectile is.
EDIT: Does it actually deaggro, or just get lost in caves or something?
If they are taking damage from bows, that could be considered a bug, since endermen aren't supposed to be able to be hit by projectiles.
Dinnerbone, will this behavior be present in all mobs eventually ( getting wet and reduced invisibility effectiveness ), or will it always be unique to wolves?