[Bug? - Fizz W] Passive damage applying on-spell effects

Fizz's W passive is applying on-spell effects, which I'm not entirely certain is intended behavior. Kassadin's W, for reference, a similar ability, only applies on-spell effects with its active portion. Seems a little broken, given you can have Liandry's and/or Rylai's constantly on someone for a permanent slow/current % health damage to go with your missing % health damage.
Report as:
Offensive Spam Harassment Incorrect Board