So, I'm not sure if this was intended when it says "up to twice per cast", but when I last hit a minion, my Rend resets, I get the 20 mana back, but then it activates again while taking the mana cost and cooldown with it without any Rend stacks out.
"up to twice per cast" applies to the mana refund meaning that you can get no more than 40 mana back from killing more than 2 enemies with rend.
her rend seems to activate itself twice (it did during the entire game I played her today). It refreshes after it kills something, but then kalista randomly uses rend right after, making it go on cooldown (unless you're extremely quick and get another stack off on something else, which is highly unlikely). I'm pretty sure this was not intended, and I hope it will be fixed as soon as possible.
