If the borg was fighting a lot of monsters (say like the Cat Lord and his 50 escorts), there was a chance that the borg would lose track of a monster and not consider it for an attack target. The problem was related to the monsters exchanging grids as they moved around so much. This is now fixed.
The borg will not teleport away uniques if they have sustained 60% damage. I saw the borg teleport away Sauron when Sauron had only 10% health left.
Borgs will be allowed to use ‘overkill’ attacks on uniques. Non-uniques still have a 2x the hp damage cap on attacks. Basically, as the borg looks for various methods of attack, he will limit the damage for each attack to twice the HP of a monster. That way if a Magic Missile is sufficient to kill a monster, the borg would not use Meteor Swarm. I saw a borg in combat with the Cat Lord, choose to use a beam lightning attack on a different line of escorts instead of attacking the Cat Lord. At the time, the Cat Lord had 47hp left. The reward for the damage was capped at 47×2. So he chose to do more collective damage by using the beam spell on a whole line of escorts.
Improved how the borg will enchant and brand stacks of ammo. This will save him some time.