This may look like a bug, but fixing it would revert the new system. At the point of the hit being registered, the opponent still has a 0.5s time span to heal himself. So when the xp is given, it's yet unclear if the hit kills the target or not. Due to it not being too important and really complicated to also get the xp calculation moved to the time when the hit is sent, we'll just keep it like that. A visual flaw that doesn't hurt.