Guild Wars 2

I started to play elementalist and I noticed that when I use Arcane Wave skill, and kill with that skill a foe, it is registered to the Sword Mastery inside of Weapon Mastery achievement points. Are those points going now right place? Why they are going to the Sword Mastery? Is that somekind of mental sword? Any opinions?

Arcane Wave is causing Sword Mastery to rise?

Most likely a bug.

Here you go:

‘Some environmental weapons and utility skills count as a specific weapon type. For example, the golem suit in Air Drop counts as a hammer, and the arcane skills count as a sword. Some, such as Lightning Hammer[verification requested] do not count towards anything.’

From the wiki.