let’s make it a bug report i guess, behaviour seems unchanged:
what seems to be happening is that with 3 projectiles the angles are calculated as if it were 4 and then the leftmost is just left out. in the previous screenshot (with modded 180 span/arc) we can see that one projectile is 90° right of center, another one 30° to the right and on 30° to the left. so with the skills base arc (45) we get one projectile 22.5° right of center, one 7.5° right and one 7.5° left which is mostly noticeable at a distance (current test patch):
the upper dummy is targeted, the lower one is actually hit.