Description (Required)

Backpack move with number buttons randomly work or not work on inventory

Steps to reproduce the Issue (Required)

https://www.youtube.com/watch?v=q0w5if8EqF0

Expected behavior (Required)

Backpack move works on the inventory with number buttons.

Server Log / Error Report

Environment (Required)

• Minecraft Version: Paper v1.15.1
• Slimefun Version: vDEV - 80 (git e3242c60)
• CS-CoreLib Version: vDEV - 398 (git 6207b63)