Ezreal's Q counts as an auto attack, and applies on hits effects including Fervor of Battle. But I tried Ezreal with 
and when I hit anything with his Q I wouldn't get a stack of the rage. But at max stacks it would proc the max stacks aoe attack. So is this a bug or does Ezreals Q not count as an auto attack for some things and not for others? Which in my opinion would be stupid.
Seems like that isn't actually a bug.
Ezreal Q is an ability, not an auto attack, that applies on on-hit effects as if it were an auto attack.
Ginsoo's stacks on auto attacks, but "Ginsoo's Rage" (the effect when fully stacked) is a on-hit effect.
So while Ezreal Q cannot stack Ginsoo's, It can proc Ginsoo's Rage
The thing about Guinsoo's Rageblade is that stacking it is considered an "on-attack" effect, not an on-hit effect. Basically, the difference between the two is on-hit effects will proc on basic attacks and abilities that proc on-hit effects, like Ezreal's Q. On the other hand, on-attack effects will only proc on actual basic attacks. This means that Ezreal's Q, and other similar abilities, will not be able to stack Guinsoo's Rageblade.
