I'm having trouble with casters, so far both Druid and Mage have had the same problem. It just runs into mobs at melee range and pulls multiple mobs before dying, and often it gets into a cast/stop casting loop where it walks towards a mob without starting the CC. My pull distance in settings is set to 35, and I've tried both Singular and Amplify Mage CCs and they both have the same issue, so I suspect it is something to do with HB itself.