What were you doing when the issue happened?

Hitting '1' a few times, toggling a stack of dirt between inventory and hotbar slot 1

What did you expect to happen?

BoP Silty Dirt and Soulbound Black Tier 3 bag to exchange places

What happened instead?

Kaboom! :(

Crashlog on pastebin/gist

http://pastebin.com/EDXQNv8a

Forge and Minecraft version?

Minecraft 1.10.2
Forge 2122
Bagginses 3.0.4e

Any other known modifications to Minecraft/Forge itself that are known to cause issues?

Any other info which might help.

Thanks!

3.0.4g (Wow, we're getting a way down the alphabet) is up on CurseForge pending approval and should fix the issue :)

Almost ready for 3.0.5! :-)