Duping with ShulkerBackpacks

[SnickoDeadMC]

Used ChestSort version
13.6.6

Used Spigot version
Paper 1.20.2 (279)

Other plugin used
https://www.spigotmc.org/resources/shulker-backpacks-1-13-1-19.67466/

Describe the bug
Contents of shulkerpack is reset to before the shulker contents was modified. This means you can dupe the contents of the shulker very easily.

To Reproduce

1. Enable automatic sorting
2. Place shulker in chest
3. Right click the shulker to open it within the chest inventory
4. Modify the shulker contents
5. Close the shulker
6. Reopen the shulker - notice the shulker did not update

Note that if you disable automatic sorting, the issue is not reproduced.

See video for example:

chestsort.dupe.1.mp4