I use to fear kite and dot / FD kill on live for 6 years, mobs do walk back to there camp when snared and the necro is FD'd.
To test this so I didnt blindly state it from memory I logged on and tried it,
here is how it went.
Code:
Cast darkness,
hit harmshield,
waited for mob to smack me a few times
hit FD,
Mob stood there for a few seconds "corpse camping" then started to walk back to camp,
I stood up,
He came after me again,
I hit FD,
He stood there for a few seconds then started walking back.
Darkness wore off,
I stood up and he kept walking.
There ARE some NPC's that will continue to corpse camp for a long wile after they kill someone, and this includes when a necro FD's however this is NOT normal behavior.