Skirmisher's Blade Smite [True Damage on Attack] goes through Tryn's Ulti AND Kayle's Ulti

Is it intended that if you use skirmer's blade and then auto attack them that the true damage portion goes through Tryn's ulti/Kayle's Ulti? Because that seems incredibly broken, you take away the one thing that actually makes the champion what it is. Seriously annoying that it goes straight through Tryn ulti/Kayle Ulti.

Yes it does to both. Making me wonder why the hell is THIS true damage is tagged as Fountain damage true damage in coding and not as normal true damage [I.E. Olaf/Cho etc]? The hell riot?