When you enter cloak the enemy instantly begins bombarding your last seen position will a volley of shells in the hopes of hitting you. If a bullet does hit you , the cloak is completely pointless except for the possible damage bonuses that you might have applied to the power. If you get way too close to an enemy, the cloak again will be pointless. Also, going invis anywhere on the map will automatically alert your position even if you are behind cover or completely out of sight from the enemy, they will patrol the last place you were seen or the place where you activated the cloak.