Minecraft version - 1.21.1
Mod loader - NeoForge
Mod version - 2.1.3
I am using the latest version available - Yes

Describe the bug
Similar to #421 and #444, when using the advanced refill backpack upgrade feature from sophisticated backpacks to refill the offhand slot while holding a 2 handed weapon, it will cause the item to permanently disappear.

To Reproduce
Steps to reproduce the behavior:
0. Hold a 2 handed weapon

1. Set the SB advanced refill upgrade filter to refill the off hand slot.
2. Watch as the backpack refills your off hand slot but the item disappears and not exist in the off hand.

Expected behavior
That the item will appear in the off hand when the 2 handed weapon is no longer held.

Screenshots or video recordings
I will attach a video recording of what occurs in a few hours. I am currently unable to do so as of the moment.

Additional context
A similar context from a different mod: Simply Swords, stated by the author of Sophisticated backpack here.