(I originally discovered this by breaking a spinning ReactorCraft Hysteresis Magnet near a Mothership Navigation Console, but I have since isolated the cause.)

It appears to happen when a FallingSand entity representing an Amun-Ra machine tries to land.

Crash Reeport: crash-2017-02-22_13.10.34-server.txt

• Steps to reproduce:

  • The Setup:
    

  • (410/2) is the ID of the Mothership Navigation Console:
    

  • This screenshot is from right after I activated the command block, and right before the FallingSand lands. The FallingSand landing causes the crash:
    

What the... why would ReactorCraft make falling sand entities out of random blocks?

Anyway, thanks for the detailed bug report. I made a fix which MIGHT work, if the actual ReactorCraft code also adds the actual meta value to the fallingblock. If it doesn't, well, I'd say that's a bug on RC's side. (Otherwise the console will turn into a radioisotope generator)

On the topic of ReactorCraft: Making falling blocks is just RC's way of making its own Event, for Rapid Unscheduled Disassembly of its MultiBlocks. Also, Reika is far to good to allow a bug like that to not get fixed.

Also, I just tried changing the command to "summon FallingSand ~ ~1.5 ~2 {TileID:410,Data:14}"

14 is the meta for that direction of MSNC, so we know it's not that.

Oh, that's how you do it. I googled about spawning sand with meta, but didn't find anything.

Hm, this should be fixed in 0.4+