Forge 1976, EvilCraft-1.9.4-0.10.7-464.jar (dev), EvilCraft-1.9.4-0.10.7-464.jar
Forge log link: https://www.dropbox.com/s/2pwreti42868dxw/catchcrash.log?dl=0

Problem:

Expected behaviour: Spirits captured by box

Steps to reproduce the problem: Set out a BEC, carry V-ring, ready V-focus Take Vengance pickaxe and beat on some coal ore. Some spirits (vengeance?) simply refuse to be captured, they can climb right over the box until they hit you or collapse. Others trigger the "tractor beam", but then crash. Upon reloading, the spirit is gone but not captured.

Side note: With two boxes in the vicinity, they can both get tractor beams. This crash was the first one where only one was placed, but when you fix that, you might want to check for spirit duplication.