I play AP 
quite often now but am finding myself in awe as to why Ludens Echo's active does not proct on GP's Q ability. When in game and you get the item, it'll work on your ult but not the Q. It kind of sucks because I'm sure this would really help in a team fight situation when using the active on Ludens.
The reason this doesn't apply the Luden's Echo damage is because Gangplank's Q is considered by the game to be a melee auto attack, so it applies on hit effects just like an auto attack would, but no spell effects, such as the Luden's Echo damage.
Works the same as Ezreal's Q with Luden's basically. It procs On-hit effects, but not On-spell effects.
This is sorta why they removed it in a few modes.
Does it work after you acquire Lich Bane (Does Lich Bane's proc cause Luden's Echo to work with Ezreal and Gangplank Qs)?
This is intentional. If it procced spell effects then you could potentially have one Q:
While hilarious, this would probably be unfair.
Spells like Gangplank Q that apply on-hit effects are essentially treated as if they are auto-attacks with a bit of bonus damage. It seems to be consistent across all similar spells, such as Ezreal's Q and Yasuo Q.
