Kalista balance

So is it intentional that 's rend and passive and how they work together are really broken? What i mean is her stacks are infinite... so she can stack a bunch of arrows in you and then hit rend for like 1200 damage.... that doesn't make sense with her being an adc and all her AA's do like 800 if shes built well. So i think there should be a cap on the amount of stacks she can have on a single target.