I get a similiar but not identical (note only callable on switch vs choose-elem-button and the lines 1716 vs 1700) error when trying to pick an icon for the factory planner mod.
Error while running event ammo-loader::on_gui_elem_changed (ID 67)
Only callable on switch.
stack traceback:
ammo-loader/lib/gui/Gui.lua:1716: in function 'func'
ammo-loader/lib/Handlers.lua:52: in function <ammo-loader/lib/Handlers.lua:39>
stack traceback:
[C]: in function 'index'
__ammo-loader/lib/gui/Gui.lua:1716: in function 'func'
ammo-loader/lib/Handlers.lua:52: in function <ammo-loader/lib/Handlers.lua:39>
Also, when I look in the logistics tab I have an item that shows as 'Unknown key: "entity-name.ammo-loader-range-extender"' that is made from 5 copper plates, 5 steel plates, and 8 iron sticks with a wire reach of 30 and supply area of 8x8 (looking like a default substation). It was available without any research from what I remember.