is mirage 3 not supposed to count as an ability or a used ability when you pre proc it?

[tidowu321]

im asking because it doesnt count as a stack for spellslinger

 

[KRSBLC]

it has been this way for a long time. mirage 3 used to not proc Mystyic Burst/Tankbuster, as well as Spellslinger; now it procs burst and buster. Guess it would be overpowered if it procs Spellslinger, its a feature.