We are currently investigating a new crash that occurs when saving the game. This is not consistent and so far it appears to only happen after creating a new world.
When creating a new world please try saving your game right away!
This patch adds some verbose logging to aid us in debugging this. If you have any information on how to reproduce this then please share with us! We are working on this and will try to get a fix out as soon as possible. Huge apologies to everyone that has ran into this.