Is your Drow by any chance the one with lowest AC and maximum HP? The AI seems to focus the one with lowest AC/maxHP pretty freakin hard, thats why Gale is the one taking most of the beating in most partys (like Druid_NPC said).
I'll have to check that.
Drow AC 13 HP 24
Shadowheart AC 14 HP 21
Astarian AC 15 HP 21
Laz'eal AC 16 HP 28
Now we need to figure out is this a bug or by design? lowest AC/maxHP seems like a strange combo so I am thinking weird bug?