[Gameplay] Lucian vs Zyra
Lucian's passive, Lightslinger - After using an ability, Lucian's next basic attack within 3 seconds shoots twice, dealing 40-60% AD physical damage on the second shot. Zyra's Plants - Using a skill near a seed causes a plant to sprout. The plant has 2 HP (increased by ranks in W). Champion attacks deal 1 damage to the plant.
Lucian vs Zyra
Zyra: sprout any plant, and stand near it Lucian: use any skill to proc Lightslinger, but do not damage the plant Lucian: use Lightslinger auto attack on a plant
Observe: Lucian will shoot the plant one time with Lightslinger, then fire the second shot elsewhere- perhaps at Zyra, or another minion in range. I have not tested how it functions while the plant is the only target in range. I assume it functions as if the first shot of Lightslinger kills the last available target, causing Lucian's second shot to be randomly shot into the air (visually).
Hypothesis: (This is where you can stop reading if you don't want the details of how I believe the bug occurs) I believe the bug occurs based on how the plants take damage, and how targeting for the second shot of Lightslinger is calculated.
How Lightslinger calculates the target for the second shot Upon clicking the target to start an auto attack with Lightslinger, and the auto attack is confirmed (projectile is created, can no longer be cancelled) Lucian's AD, Armor Pen, Crit, and the target's defense and HP have already been looked at. Level one Lucian, not counting any additional bonuses from Runes/Masteries/Items has 57.5 AD. This means, to a target with 0 armor, he will do 57.5 damage.
Let's assume Minion A has 60 HP and 0 armor. Lucian's first auto attack from Lightslinger will see this, and the minion is calculated to now have 2.5 HP left, after the first Auto Attack hits. 57.5 is not greater than 60. The second shot will continue to target this minion, as it will survive the first attack.
Now let's assume Minion B has 40 HP and 0 armor. Lucian's first auto attack from Lightslinger is doing 57.5 damage - and therefore will kill the minion. 57.5 is greater than 40. The second shot will now target something other than Minion B, because it will not survive the first attack.
Now let's look at Zyra's plant. Zyra's Plant has 2 HP and 0 armor. The first auto attack from Lightslinger has 57.5 AD, and against the plant's 0 armor deals 57.5 damage. 57.5 is greater 2, and therefore, the auto attack believes the attack will slay the plant, and will now target something other than that plant for the second shot.
This is where the problem lies. The plant does not take 57.5 damage to its 2 HP. It has special rules, causing it to take 1 damage to its 2 HP. The plant survives the first auto attack, but this occurs AFTER the second Lightslinger attack has been calculated and targeted.
TL;DR Lucian's passive doesn't double shot Zyra's plants.