3872.143 Error MainLoop.cpp:1195: Exception at tick 102022786: The mod LTN Combinator caused a non-recoverable error.
Please report this error to the mod author.

Error while running event LTN_Combinator::on_gui_elem_changed (ID 67)
LTN_Combinator/scripts/ltn-combinator.lua:263: bad argument #3 of 4 to 'set_signal' (table expected, got nil)
stack traceback:
[C]: in function 'set_signal'
LTN_Combinator/scripts/ltn-combinator.lua:263: in function 'set_slot'
LTN_Combinator/scripts/ltnc-gui.lua:627: in function '?'
LTN_Combinator/scripts/ltnc-events.lua:38: in function <LTN_Combinator/scripts/ltnc-events.lua:36>
3872.143 Error ServerMultiplayerManager.cpp:92: MultiplayerManager failed: "The mod LTN Combinator caused a non-recoverable error.
Please report this error to the mod author.

Error while running event LTN_Combinator::on_gui_elem_changed (ID 67)
LTN_Combinator/scripts/ltn-combinator.lua:263: bad argument #3 of 4 to 'set_signal' (table expected, got nil)
stack traceback:
[C]: in function 'set_signal'
LTN_Combinator/scripts/ltn-combinator.lua:263: in function 'set_slot'
LTN_Combinator/scripts/ltnc-gui.lua:627: in function '?'
LTN_Combinator/scripts/ltnc-events.lua:38: in function <LTN_Combinator/scripts/ltnc-events.lua:36>"
3872.143 Info ServerMultiplayerManager.cpp:776: updateTick(102022786) changing state from(InGame) to(Failed)
3872.159 Quitting: multiplayer error.
3872.605 Info ServerMultiplayerManager.cpp:138: Quitting multiplayer connection.
3872.605 Info ServerMultiplayerManager.cpp:776: updateTick(4294967295) changing state from(Failed) to(Closed)
3872.669 Info UDPSocket.cpp:218: Closing socket
3872.669 Info UDPSocket.cpp:248: Socket closed
3872.670 Goodbye

do you have additional information for me, a way to reproduce it?

this was experienced when a friend with a laggy PC (FPS/UPS dropping) was opening the combinator and clicked on one of the filter tile slots before the redraw finished.

the interface he saw looked more like the original combinator and not this custom UI, so i think the latency caused a race condition. maybe you can gracefully error out if the table is nil.

thanks for the feedback. I uploaded a new version with some additional checks.

we haven't reproduced this issue since, but i suppose that could be luck. thank you!