I haven't quinted these ghostly mobs on Brother Island in a long time but I went back there today on a lark and to test some new spells. THIS guy cannot be snared or rooted, which messes up a quad or quint, since he spawns in the same area as the other wanderer ghosts. I don't recall this ever happening before and I must have killed 100's of these wanderers, all types, in the past. I wonder if they ninja-nerfed this guy to make quinting harder. At least he doesn't summon.
Yeah, dug into logs and back in Dec 2014 this mob was quite snareable. Now, "Your target is immune to changes in its run speed", unlike the lost and listless wanderers who spawn in the same area.