(I'd say it is a low priority bug) I just created a new world and when I spawned, the bonus chest was in the water. I tried to recreate the bug and once the chest was in land, but others 4 times it was in water (attached screenshots).
Reproduce
Create a new world with bonus chest enabled with seed: 3648193828345539121
Coordinates: 241 63 -250
Expected Result
Bonus chest placed in land.
Hello, thanks for creating a report! We're actually already tracking this issue in MC-29613. If you have any more information to add about the issue, feel free to leave a comment there 🙂