Shift + left click on stacked Sophisticated Backpack takes 2 stacks of items instead of one #67

Minecraft Version

1.21.1 (LTS)

Mod Loader

NeoForge

Describe the Issue

This was posted on our issue tracker, and I've confirmed it is still a problem: FTBTeam/FTB-Modpack-Issues#10893

I was able to reproduce this bug very easily even outside of our pack, allowing me to narrow it down to InvEssentials mod

To Reproduce
Steps to reproduce the behavior:

1. Install this mod, Sophisticated Core, Storage, and Backpack
2. Equip any backpack with a gold-tier or higher stack upgrade
3. Add more than 2 stacks of items to any slot
4. Shift + Left-click on the item and move your mouse slightly as you do it
5. Pulls 2 stacks ONLY on the first interaction with that itemstack (per time you open the backpack)

Expected behavior
Expect only 1 stack to be pulled out

Versions
Inv Essentials: 21.1.12
Soph Suite:

Logs

This is a very minimalist log. Very narrow modlist, got into the game, replicated the bug, and closed the game. Let me know if you need a more in-depth log:
https://pastebin.com/4xi76TWz