I play a decent amount of AD Kennen. His passive w is every 4 hits, he places another mark and deals % based ad damage. I ran one of the new items Runaan's Hurricane as it is suppose to add on hit effects to secondary targets. To my knowledge the passive w is worded on hit, but does not actually add the on hit effect when it procs the passive to the secondary targets. If its working as intended awesome, but I believe it should work at least the way its worded in game.

Thanks!

The stun effect + bonus damage is an attack enhancement, not an onhit effect.

That said, hurricane only helps to build up the counter to trigger the effect, but will not deal the bonus magic damage or stun the targets hit by the bolts.