Carrion Raven Barbarian: Tusk of the Rampaging Mammoth

I believe it is broken. It says "You can use an action and spend 3 maneuver points to strike an enemy with the overwhelming force of a rampaging mammoth. When you do, make a melee weapon attack against a creature within 5 feet. On a hit, you deal 3d12 damage in addition to your attack’s normal damage. If the creature is Huge or smaller, you push the creature 15 feet." yet on the D&D Character Sheet, it doesn't add proficiency bonus to hit since melee weapon attack and it has 3d12 + Strength Bonus, which it shouldn't since all it does is add 3d12 to the weapon damage's normal damage.