We're moving to 1.17 now, this update fixes a lot of issues with 1.16 and below just in case you aren't ready to update to 1.17.

• Fixed NPE occuring when Jigsaw fails to find Object in pool. Now just produces a warning in the console like it should
• Fixed pointless copies of lists being created within PlannedStructure
• Fixed mobs spawning within other blocks and suffocating on spawn
• Fixed creating a jigsaw with a non existent object causing jigsaw commands to lock up (#377)
• Fixed editing a non existent jigsaw just not doing anything

• Fixed Jigsaws not placing TileStates
• Fixed NPE when banners, signs or skulls try to be rotated to be up or down

• Fixed double sided connectors not working properly
• Fixed skulls not being able to be rotated when they are placed on an angle that isn't perfectly straight (north, south, east, west)