Can life steal not heal for more health than the target has left?

Really upsetting to see an ADC hit a minion with almost no health left and get a ton of HP back. Like, how does that even work? If the minion/monster/champ only has 50hp left, they should only be able to heal a max of 50hp from hitting it.

They'll still be able to heal themselves to full on a fresh minion wave, just wont pull shenanigans and heal themselves more than they should be able to considering how much health their target actually has.