Taliyah passive VS Death dance

So basically your passive dont work when you are in fight. When you attack someone with Death Dance you dont really deal damage to him, this is damage from item. But still your passive dont work untill DD stop its damge. I dont think this should work this way? I mean this is damage from item, if this works this way why does Summon Aeras/Comet dont proc?

Basically Death Dance is huge counter to Taliyah right now, it switch off her most OP ability. Propably this works on other out of fight passives / item passives.