Lucian and Runaan's

Just played a game where i was theorycrafting my 45% thunderlords Lucian and I decided to try to pick up a Runaans because i was really far ahead and it gives crit for essence reaver and I noticed that my Runaan's was not procing on the first auto after i used an ability. Whenever Lucian uses his passive it just doesn't uses runaan's. Personally it should shoot at least one bolt when lucian uses his passive. Shooting two bolts would probably get out of hand. Is this a bug or intended?