I did build some landfill over small lakes. I didn't look deeper into it, but maybe it's a Bug with pathfinding? I'll post this bug also in Rampant Mod.
The mod Construction Drones (0.5.5) caused a non-recoverable error.
Please report this error to the mod author.
Error while running event Construction_Drones::on_script_path_request_finished (ID 112)
The mod Rampant (0.18.11) caused a non-recoverable error.
Please report this error to the mod author.
Error while running event Rampant::on_robot_built_tile (ID 47)
Rampant/control.lua:783: attempt to index field 'item' (a nil value)
stack traceback:
Rampant/control.lua:783: in function <Rampant/control.lua:779>
stack traceback:
Construction_Drones/script/construction_drone.lua:2180: in function <Construction_Drones/script/construction_drone.lua:2125>
(...tail calls...)
Construction_Drones/script/construction_drone.lua:2680: in function 'handler'
core/lualib/event_handler.lua:47: in function <core/lualib/event_handler.lua:45>
stack traceback:
[C]: in function 'raise_event'
Construction_Drones/script/construction_drone.lua:2180: in function <Construction_Drones/script/construction_drone.lua:2125>
(...tail calls...)
Construction_Drones/script/construction_drone.lua:2680: in function 'handler'
core/lualib/event_handler.lua:47: in function <core/lualib/event_handler.lua:45>