In Tol Barad the Siege counter never goes up from 1/3 for me for Towers of Power. I got credit for 5 and 3 in the achievement Tol Barad Saboteur in the last two games but not more than 1/3. Sometimes during the game I have seen it go from 0/3, to 1/3 and back to 0/3. Seems to be super weird. I know others have gotten the achievement just by being in the vicinity of a siege getting killed but what gives?