Arti able to destroy commanders under water

I don't remember this previously being an issue, but recently the experimental arti has started to be able to be able to hit commanders under the water.

When playing as assassination, this is completely game destroying. You can't defend against this.

At least you can attempt to defend from the other experimental units.

Has something changed that is allowing this?

Probably the commander was in shallow water. Needed to be deeper in order to avoid splash damage from the shell exploding at the water's surface.

It has always been like this. You need deep water to be safe.