Yes it’s bad modelling. Lots of bridges did this, until recently. We even set up a special topic, to report bridges that allow flying under. Most bridges got repaired with the SU-5… but not everything… London Tower Bridge won’t allow it either.
NOTE: just tested it with ICON… it has issues indeed. When you approach, you see the shadow of the “wand” in the water…
…with damage assist off, you’ll get a black screen immediately. But with the assistant on and enough airspeed, you can fly through the “wand”, you just hear a short crack.