Bug/Issue Lua Crash in Custom Monsters

First of all, by custom monsters, I mean monsters whose JSON has been written in by hand. These monsters are akin to those generated by planets, except their parts have been hand picked. You can spawn them in with the /spawnmonster command.

I run a private server for friends and myself, and one of them copied and pasted a command to spawn a custom monster. When he used it in single player, it worked wonderfully. However, when I do so on the server, problems occur. (I tested it in single player as well, and it worked.)

The monster spawns alright, but when it tries to attack, the server catches a lua crash and shuts down the world, sending everyone on it back to their ships.

The server is modded, but I temporarily removed the mods on both client and server, and the issue remained. (The server, BTW, is a Creeperhost Cave Spider.) I tested on a localhost server, and the issue was non existent.

Click to view relevant excerpt from the server's log.

At this point, I believe that the issue is in the server binary for Linux.