1. Cast Snowball on an enemy (but do not use Launch Snowball)
2. Die before the rolling begins

Result: Snowball is canceled, but Tusk still has the Launch Snowball sub-ability in the UI, instead of Snowball. Using it launches a harmless Snowball. However, it can be used to get the Snowball's visual effect get stuck on enemies:

3. Get within Snowball cast range of an enemy
4. Cast the Launch Snowball sub-ability which was left over from step 2
5. While the harmless Snowball is rolling towards the enemy, cast Snowball on an enemy again

Result: Once the harmless snowball reaches the target, the target gets stunned and damaged. The new cast Snowball gets canceled as soon as that happens. On top of that, the Snowball gets stuck on the unit permanentally. Also, 3 seconds after the new Snowball cast which got canceled, another harmless snowball gets launched towards the new target.

Expected: When dying during Snowball, the spell gets fully canceled and Tusk gets the Snowball ability back when dying before launching.