Hello,
It looks like the update here has created a gap in a couple of boundary relations.  https://www.openstreetmap.org/relation/12409614#map=19/54.856662/-6.763608 has a gap under the bridge and https://www.openstreetmap.org/relation/12403345#map=19/54.856662/-6.763608 also.
The new culvert needs adding to both relations with a role of "outer".
I think that iD will do this automatically unless you redraw it manually.
Best Regards,
Andy