the game crashed after a little while and the world, I was playing on, is not loading anymore (game crashing again)

error: The game crashed whilst exception in server tick loop
Error: java.lang.IllegalArgumentException: ChunkNibbleArrays should be 2048 bytes not: 0

ChunkNibbleArrays? Is that for certain related to Mo' Bends? What other mods do you have installed?

only mobends

I think this happens often when switching Minecraft versions, there are apparently ways to fix this: https://shockbyte.com/billing/knowledgebase/110/javalangIllegalArgumentException-ChunkNibbleArrays-should-be-2048-bytes-not-0.html.

This seems to have nothing to do with Mo' Bends though.