Truck errors and a bridge over water.

Trucks report that they cannot plot a route to the bridge, even though its supports are standing in the water.

you must use Amphibious Trucks to build the over-water portions of the bridge, such as the one shown

I am aware of that. The trucks are sending notifications that they cannot build the bridge—that is the problem. They shouldn't be trying to build it.

Is there a ramp to the water for the trucks

No. It shouldn't be there.

I mean a ramp into the water so the amphibious trucks can get in the water

Trucks could build this. A part is over the land.

Yes, trucks could be built in theory, but in practice, they can't. It might be worth adding the ability to select which vehicle types are allowed to participate in constructing a structure.

That "over the land"part is often some cliff that trucks can never reach.

the real problem is this prohibits amphibious trucks from getting the job

Seems like that only trucks built after the bridge ghost are affected.