If you build a bridge (or have had one spawn naturally) and you build a wall over it while "rebuild destroyed structures" mode is active, then have the wall and bridge destroyed (by something like a grenade) the wall will automatically have a blueprint placed and will be built, despite the bridge being gone.
Steps to reproduce:
1. Build/Find a bridge
2. Build a wall over the bridge
3. Ensure rebuild destroyed structures mode is active
4. Destroy wall and bridge with a grenade
Steps to reproduce:
1. Build/Find a bridge
2. Build a wall over the bridge
3. Ensure rebuild destroyed structures mode is active
4. Destroy wall and bridge with a grenade