In luabind, why does lua_close(lua_State* L) seem to not need to be called?

I'm writing a raytracer in C++11 and if I comment out the following line: http://ift.tt/2hC1NsR

it compiles and generates a picture, properly reading function calls from a lua file that defines the scene. If I uncomment L59, the program throws an error that a pointer is being freed when it was never initialized.

The error thrown is

raytrace(10818,0x7fffae7383c0) malloc: *** error for object 0x7ffca4e09e40: pointer being freed was not allocated *** set a breakpoint in malloc_error_break to debug [1] 10818 abort ./raytrace scenes/simple.lua

I can't find any documentation about this, whether it's an API change or what's going on. I just find it very strange that I create a lua_State object with open and later never need to do anything to close it.