Mod loader: NeoForge 21.1.133
Mod: 1.21.1-10.1.16

1. Describe the bug
   Items duplicate when you transfer a full stack in your inventory when you have not enough space to fit the whole stack.

2. Write steps to reproduce the bug
   Put a full stack of an item in the backpack
   Fill your Inventory till only one slot is left and put 1 of the same items you put in the backpack
   Take the stack with shift + click in your Inventory
   Close backpack
   Open backpack
   Backpack still contains stack from which you took 63 Items

3. What is expected behaviour
   The Items shouldn't duplicate

4. Screenshots (If applicable)
   https://github.com/user-attachments/assets/e2b4020c-5020-4ed3-b2e5-17cd7006640a

https://www.curseforge.com/minecraft/mc-mods/travelers-backpack
Fixed