Ahri q doesnt proc luden's, 100% reproduction rate
im jk lol the title is just a bait for riot to care about this thread here are some rengar q item bugs though, some of which that have been out for OVER 7 months Shiv/RFC: Jumping from bush or ult won't trigger the lightning passive on either one of these items, and RFC doesn't extend jump range. You can do this by jumping to a minion in a custom.
Triforce/Iceborn: If you trigger the spellblade passive with w e r and then use q with it, the bonus damage is not applied (iceborn slow zone still appears). If you only Q the damage is applied. Example: you bola an enemy and then walk up and Q them. You won't deal extra damage.
Deadmans plate: Using Q with deadmans stacks doesn't add the bonus damage. Only basic attacks will.