IWT and AutoLoot

[Khatovar]

Also make sure your slaves have automatic loot on {Esc > Interface > Controls > Auto Loot}

[dRiN]

Maybe it is in the bind you send during the looting. In my experience, shift + lag can sometimes cause these non looting issues. I believe it is an option the use a modifier to suppress the auto loot. Maybe you can remove this option. Or change something in your keymappings.