Water mobs and aggro
Iruwen Evillan, Human Mesmer on Drakkar Lake
I think it might be intentional, as mobs that cannot go on ground do not usually engage in combat unless you’re underwater. Therefor, the Tuna doesn’t try to fight/ go red into combat.
It has always been like that with water mobs. Probably because according to the pathing data they CAN reach you so it doesn’t trigger the invulnerable for sniping but the mob AI prevents it from walking out of the water. For some reason only some mobs respond by trying to run away/out of range.