concreep causes a crash on sandbox shortly after starting works fine on freeplay

The mod Concreep Refilled redux (1.0.2) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event concreep-refilled_redux::on_nth_tick(60)
concreep-refilled_redux/control.lua:31: attempt to get length of local 'source' (a nil value)
stack traceback:
concreep-refilled_redux/control.lua:31: in function 'array_shallowcopy'
concreep-refilled_redux/control.lua:158: in function '_reinit_reentrant_level1_start'
concreep-refilled_redux/control.lua:132: in function '_reinit_reentrant'
concreep-refilled_redux/control.lua:119: in function 'reinit'
concreep-refilled_redux/control.lua:264: in function <concreep-refilled_redux/control.lua:259>

Very late, but I'm looking into this.

I was testing in Sandbox all day today and didn't have this issue, so I'm assuming it's solved. Let me know if you see it again, and preferably share your save.