Using the vanilla bundle experiment datapack, any item can be easily duped by placing a full bundle in a Spellcaster/Trinket bag and attempting to take items out of the bundle.

May I also add to this:
Spellcaster and Trinkiet Bags are not locked when opened - moving bags around will visually clear all items form the HUD and putting anything into this hud will void items. Putting bag back into it's original slot will do nothing.

Couldn't replicate the Bundle dupe on my end and I don't know if it's because it got fixed or if one of my other mods in my pack somehow prevents it too...

blacklisting the bundle and locking the slots with the bags should have patched this

I remember checking the update when it dropped at the time and I can say that both Bundle and non-sticking Bag changes fixed both issues.