This was found first in the ATM3 modpack, and then was tested on a custom modpack to remove all other mods.

Forge: 14.23.3.2674 and 14.23.3.2679
Plants: 2.8.2 and 2.8.4
Botania: r1. 10-354

All the Mods 3 5.9.4b

Basically anytime the sword is swung at a mob, minecraft crashes. This can be done on both singleplayer worlds and multiplayer worlds.

Crash Report: https://pastebin.com/RKiMF1dc

seems like botania updated. bleh