This had been previously reported on the PTS that it was not calculating the damage correctly.

I would like to report that it is still not computing the bonus damage correctly.

• Major Expedition should provide 180 weapon and spell damage and it is only providing 70.
• Major Expedition is not stacking with Ring of the Wild Hunt it's either or (probably because it caps).
• Celerity doesn't appear to be affecting the buff.
• The Steed Mundus does not appear to be affecting the buff.
• Swift Jewelry does not appear to be affecting the buff.
• Activating the banner I get 23 weapon and spell damage from... something, it's really hard to tell from what because there doesn't appear to be a clear method of determining what my movement speed bonus is in game.
• Major Gallop increases the weapon and spell damage the same 70 points I would get from Major Expedition or the Ring of the Wild Hunt.
• Sprinting also increases your weapon and spell damage.
• When crouching you lose all the bonus damage.

Currently I am only able to get this buff to 93 weapon and spell damage. Not really worth it.