I kept dying doing the quest
Stormheim's Salvation due to the
Felskorn Channelers not being burned down. I added 'ImmediatelySwitchToHighestPriorityTarget="True"' to the CustomBehavior tag and it worked very well:
<CustomBehavior File="KillUntilComplete" QuestId="40005" ImmediatelySwitchToHighestPriorityTarget="True" QuestObjectiveIndex="1" X="2455.637" Y="913.7571" Z="596.142" >
<PursuitList>
<PursueUnit Id="96489" Priority="500" />
<PursueUnit Id="92224" Priority="300" />
<PursueUnit Id="96491" Priority="300" />
<PursueUnit Id="96090" Priority="300" />
<PursueUnit Id="92307" Priority="100" />
</PursuitList>
</CustomBehavior>
File: [N-Quest] Stormheim [Echo].xml