Shaco Clone being lower level than 6

I was in an ARAM game and my entire team got pretty badly messed up by going in on a level 5 shaco playing very dangerously. The problem was that this was his clone. Is this intended or is this a bug? Half of my team argued the former and the other half the latter. The argument was that because Shaco himself was out of vision then we couldn't see him level up and thus his clone appeared to be level 5, which was when we last saw him. Even if this is intended, it's a rather oppressive mechanic for a player to be punished for making a wrong judgement based on false information that a player would expect the game to provide, i.e. the level of an enemy champion that is standing directly in front of you in vision.