In the Caves & Cliffs experimental world, you'll often see shipwrecks generating on ocean water with one block depth, or completely on the surface. It should be less likely to generate like that.

Step to Reproduce
1. Create a new world with caves & cliffs experimental toggle on.
2. Find a shipwreck. (either with /locate or by just flying around)

Observed Result
Shipwreck often generates on the surface, some generate on ocean water with one block depth, some generate completely exposed on the surface.

Exposed Result
Most shipwrecks should generate on the seafloor.

Note: The seed and the coords are on the screenshot.