u/Flechashe

As you probably know, you can cancel Smolder's E by using another ability. For some reason, when Arcane Aim is active, Q cannot be used to do this (unless you're at very close range, as you can see in the video).

Apparently, it's reducing your Q range to 100 units, the amount that the item gives in range. Normally, during E your attack range is reduced to 0 but your Q range remains the same and you can use it to cancel E.