Darius' ult resets off of circumstances when it clearly doesn't execute the enemy.

It sounds strange for a Darius main to point this bug out, but that's how it is. Sometimes when Darius ult's an enemy a split second before they die of another cause, the reset buff is activated. His passive usually does not trigger off of this bug. This isn't problematic at all for the Darius player - the cooldown is based off of the first cast, and the reset can only help. However, a bug is a bug.