From the PTS patch notes:
Silver Leash (Silver Bolts morph): Increased the pull damage for this ability by 33%
It's already been pointed out to ZOS multiple times already, but the pull only works on undead which means the first hit of silver bolts has knocked them down and given them CC immunity, therefore you can NEVER pull an enemy player OR npc to you using this morph. But, thanks for increasing the damage the pull does guys...