Forge version: 2589 client
Botania version: 252
Link to crash log: gist
Steps to reproduce:

1. Clients loads the chunk and crashes. Guess it while TileAltar.update()

I am aware that I am one version behind, but don't think that this crash is covered by 253. Can't really test tbh.

What I expected to happen:
Client does not crash
What happened instead:
Client crashes

If you need more info or the crash is fixed by 253 feel free to close the ticket or let me know

We need to actually know what you were doing to cause this. Were you loading a sp world? Joining a server? Exploring terrain?

Oh it's on a server. Every player-client that tried to load this chunk, got a crash. No error server-side.
Removed the altar on that said positon via a command and didn't happen again since that. I know that this isn't very helpful, but nothing more info-wise I could provide