Try looking at this savegame: link.
My sovereign is traveling with a noblewoman. Normally, my sovereign has 4 movement points, and the noblewoman has 1 movement point. When they travel together, both have only 1 movement point.
When they move, the sovereign end up with 0 remaining movement, but the noblewoman still has 1 movement point left, so she can continue moving if she leaves the sovereign.
Expected behavior (?): After moving, the sovereign should have 3 remaining movement points, and the noblewoman should have 0.
