Game crash when you put watherfill in Range 2x2 on the direct Side of the Station
Report:
Error while running event LTN_Tracker::on_tick (ID 0)
LTN_Tracker/script/data_processing.lua:161: bad argument #1 to 'pairs' (table expected, got nil)
stack traceback:
[C]: in function 'pairs'
LTN_Tracker/script/data_processing.lua:161: in function 'check_for_new_stops'
LTN_Tracker/script/data_processing.lua:330: in function <LTN_Tracker/script/data_processing.lua:289>

I was not able to reproduce your issue. You are probably destroying part of the LTN stop with waterfill in exactly the wrong moment.
I am going to need your save file to reproduce the issue. If you don't want to link it publicly, you can also PM me on the forums.