In the Curse of Strahd, there is a magic item known as the Blood Spear. On page 221, it says it requires attunement and when you hit with a melee attack and reduce the HP of the creature to 0, the wielder gains 2d6 temporary hit points.
Then on page 200, the book says anyone can wield the spear but only the character chosen by Kavan (the original owner) gains +2 bonus to attack and damage rolls made with the weapon.
On the Dungeon Master's Guide pages 137 and 138, it says that "Some magical item require a creature to form a bond with them before their magical properties can be used..." and "Without becoming attuned to an item that requires attunement, a creature gains only its nonmagical benefits, unless its description states otherwise."
Then on DMG page 213, it lists +2 Weapons and there's no mention of attunement. The other odd thing is +2 Weapons are typically rare but the Blood Spear is uncommon.
My question is does the +2 to attack and damage rolls require attunement as well? I just think it's odd that this feature of the weapon isn't in the magic item's listing but on the page where the PC actually finds the weapon. It almost makes me think this feature doesn't require attunement but I'd like to hear others weigh in on this quandry.