YABBA-1.1.2.41
ChestTransporter-1.12.2-2.8.8
Cyclic-1.12.2-1.17.16

In an attempt to not loose 2 of the contents to an open inventory spot every time a barrel is moved, I tried using the Obsidian Chest Transporter and ended up with a 2nd empty barrel loose on the floor and the full barrel (with all contents) in my inventory tool. This was the same case for the Cyclic Bag of Holding.

At least its only an empty barrel. You can use Barrel Wrench to drop barrels properly

Reported to mod author: cubex2/chesttransporter#32