Since you're using Jamba, try using the AdvancedLoot module in Jamba. It replaces the blizzard auto-loot and has a workaround in place to keep your slaves from getting stuck trying to loot. It pretty much just closes the window after it tries to loot so the slave can try and loot again with a fresh loot window - I hammer my interact with target on corpses and have no trouble looting everything consistently.