fabric 1.21

Whenever I place items into my backpack, the game crashes, typically 5-10 seconds later.
This occurs both when I pick up and drag items into the backpack, as well as when I shift-click to add them.
I do have the Mouse Tweaks addon installed, but it was functioning properly yesterday

message.txt

I suggest updating fabric api to latest 1.21.1 release and see if it helps