Using the number hotkeys, the Bag of Tricks can be duplicated and items can be lost. Here's a setup:

• Place a Bag of Tricks in slot 1
• Place anything in slot 2
• Open the bag
• Hover the mouse over the slot 2 item/block
• Press 1

The bag and the other item/block seem to switch, but as soon as the bag is closed, two copies of the bag appear, one in the first slot, and one in the other slot, replacing the item you switched it with, the one in slot 2 above.

It's a bit annoying, I've lost important items because of this.

Also, I forgot to mention, I'm using Inventory Tweaks alongside this mod. The switching items feature above is from InvTweaks.