Version Info

• Minecraft 1.20.1
• Packed Up, 1.0.30-forge-mc1.20
• Core lib, 1.1.17-forge-mc1.20.1

Description of the Bug
When pressing O to open the back, it works. Pressing again to close the bag, closes the back, and reopens when releasing the key.

Steps to Reproduce

1. Equip backpack
2. Press O to open
3. Press O to close

I fixed it now in Packed Up version 1.0.30a/b/c (depending on modloader and Minecraft version).
Thank you for reporting the issue!