It seems that mobs in battlegrounds only have one "slot" for drops. Either bag of coins or an item or nothing at all. Only in Abermenai i sometimes had mobs, which have dropped 2 items (shoes)
Shouldn't they have a slot for everything they can drop?
ie
bag of coins 75%
rog 1.5 %
small/large/big chest 3% ? (mobs in bg don't drop chests at the moment, even when linked)