[2020] Cannot exert vaal ground slam?

I was planning on doing a zerker that focuses on powering up vaal ground slam to stupid degrees, and it appears vaal ground slam just doesn't consume a charge of exert and doesn't get doubled by intimidating cry. This isn't mentioned anywhere even though other mechanics specifically mention vaal skills as not functional.

"Exerts the next 2 melee attacks you perform" is all it says, yet VGS is a melee attack. So I guess this is a PSA as well for people planning on doing vaal skill builds