why can`t caption assigned the armor drop from boss?(TDB 335.60)

E.g:the first boss Koralon the Flame Watcher(entry:35013) in Archavon instance ,it dropped
the item Zabra’s Pants of Conquest(entry:48099) and the Hellscream’s Legguards of Conquest

this and some other boss in instance,its dropped item cant use caption asssigned to members in
group and the groups caption also cant pick up it

why? i am use the tdb 335.60 release
can help me?thanks very much