I was putting a polished stone slab from Quark near a petal apothecary using a building blocks trowel when this crash happened. Not sure if it's botania's issue, due to the multiple mods involved, but figured I'd report.

Using pre-release build 301

https://gist.github.com/gazpachoking/5dc5ec9c3344112227a11a941b23a931

Dupe of #221

Yes dupe, and it's a Forge bug, pending a response from them. I'll probably add some workaround checks in the meantime if they don't respond soon

Oops, sorry about the dupe. Saw this in your forge issue,

Note that this ONLY happens when digging in survival

Just thought I'd mention that I was placing a block when it happened, and it now happens every time I load the world.