Describe the bug
Dupe bug with the new offhand mechanic in the inventory

To Reproduce
Steps to reproduce the behavior:

1. Open a backpack in the offhand
2. Press F to get the off hand item
3. Drop the backpack
4. Remove the items from the backpack inventory
5. Duped, as the droped backpack still contains the items

Expected behavior
Should block the F key in the offhand or close the gui instantly when pressed

Screenshots
If applicable, add screenshots to help explain your problem.

Versions

• Mod version: 1.11.0.67-SNAPSHOT
• Minecraft version: 1.16.1
• Forge version: 32.0.57
• UTeamCore version: 3.1.0.161-SNAPSHOT

Log (if crash occures)
Link to crash log