The day after a patch is released is usually the most dangerous time to play League of Legends. Although most tweaks pass their testing phase on the PBE without issue, a few bugs may go unnoticed due to last minute changes. #
This is a situation that occurs more frequently than it seems, and in the case of Patch 11.17, affected Kalista to the point Riot created a monster.
Kalista and her double dose of damage
Popular content creator Vandiril, an expert in unmasking programming errors in League, exposed how Kalista was capable of launching a double auto-attack.
By means of a combination of mouse clicks, it was possible to launch two simultaneous attacks on a single enemy, or attack two rival units at the same time.
The problem was that this was an easy bug to use unintentionally, and easy to disguise for players who wanted to take advantage of it.
Due to this, it's difficuly for Riot to apply sanctions to those intentionally using the bug to gain an advantage. Despite the bug being live only a few hours, it was enough to see Kalista's winrate increase a couple of percentage points.
Fortunately, post-patch bugs don't usually linger in the game for too long. As with a Ryze bug a couple of patches ago, this Kalista bug was hotfixed less than 24 hours later.