Input underneathies as start and exit underneathies as last part are treated like regular belts and are not connected with a corresponding exit/input underneathie. Instead regular belts are used in "allow underneathies but prefer on ground belts", leading to non-connected paths.

Thanks for mentioning that. Will fix in next version.

Nice, thanks :)

exit underneath belt as last part is now supported. input as starting point is a little bit tricky but will be fixed eventually in next version :D