i got the following crash when sorting a 'loot chest' with inv tweaks middle mouse click.
https://gist.github.com/the-creamster/415c8af6eed8d123e84281c150fe7e7a

Edit:
it triggered on the 2nd chest
Edit 2:
the trigger this time was lft ctrl for sprint boost while flying and exploring
Edit 3:
Its triggering at random points during modpack/world loading/exploration now with random mod references in the crash log