Seems like when something wimpies or dies from the new trapper "powder" skills (stench cloud, blister agent, abrasive powder), they stop being area attacks. For example while fighting three NPCs (two dirty thieves, a rat...was aiming at the second thief in this log):

(220p 101m 513mv 10026tnl (14.31%) wilderness) stench
You scatter a packet of dust into an olive-green cloud.
A dirty thief looks uncomfortable, but quickly recovers.
Your foul-smelling cloud injures a dirty thief.
A dirty thief has fled!
A dirty thief is writhing in agony.

(220p 86m 513mv 10026tnl (14.31%) wilderness)
A dirty thief dodges your slash.
A dirty thief parries your pierce.
Your slash EVISCERATES a dirty thief!
With a quick blow you deflect a giant swamp rat's bite aside.
You parry a dirty thief's pierce.
A dirty thief is writhing in agony.

(220p 86m 513mv 10026tnl (14.31%) wilderness) stench
You scatter a packet of dust into an olive-green cloud.
A giant swamp rat looks nauseated as the stench washes over it.
Your foul-smelling cloud wounds a giant swamp rat.
A dirty thief looks nauseated as the stench washes over him.
Your foul-smelling cloud wounds a dirty thief.
A dirty thief is writhing in agony.

n/t