Describe the bug
Backpacks are duped and can be placed multiple times on my multiplayer server.
Video showcasing the bug so I don't have to explain stuff: https://youtu.be/AQoaorvglfQ
List of all mods: https://imgur.com/a/zbeRF8b (client) \ https://imgur.com/a/iJCxpH0 (server)
List of all plugins: https://imgur.com/a/JZuMozb
Error in question: https://pastebin.com/ZDRFn1kU
Server is running on Mohist, Forge 36.2.39.

To Reproduce

1. Take backpack in your hands
2. Put items inside (optional)
3. Shift+right click to place the bag
4. It is placed down, your hand is empty, but you can place additional backpacks
5. A lot of errors appear in the logs
6. Continue shift+right clicking, backpacks are still placed
7. Can break all backpacks with all items still inside, thus creating an easy dupe

Expected behavior
Backpack should be placed on the ground and you shouldn't be able to continue placing stuff down.

I have fixed this issue by updating Mohist to the latest version. Apologies.

Turns out the issue is not this mod, as Astral Sorcery suffers from this too. Can't find any solution.