For some reason Warptorio has an underground pipe which isn't underground.
As a simple solution, please disable the "Extra bonuses" in the mod settings.
If you want to keep the extra bonuses, add this as a custom bonus string in the settings (haven't tested, but should work):
-pipe-to-ground:fluid_box.pipe_connections.2.max_underground_distance.?=add 2
Regardless, I'll fix it for the next version