I've just had some very weird interaction between Typhoon claws and Runaan's Hurricane.
1/ I played Kayle and was amazed that Typhoon claws ticked on the Runaan's Hurricane bolts while her E was active : 1 AA counts to three ticks of Typhoon claws if it hits three targets.
2/ It didn't worked on Kog'Maw, where every AA counts only for one tick even if runaan's hurricane hit three targets.
I believe Kayle's behavior to be a bug and Kog'Maw's one to be intended (mainly because of how strong it was :P ).
Reproduction : Just pick Typhoon claws and Runaan's Hurricane and watch the Typhoon claws' counter while you auto attack.
In my opinion, Runaan's Hurricane, Typhoon claws and Sated devourer all have very unclear interactions with the rest of the spells (typically what does/doesn't proc on it). I feel like there is probably some rework and/or clarification to do on the whole interaction of on-hit effects with theses items.