Seed: 490798691970183764
Coordinates: Imprinted on the screenshot below

I just stumbled upon an upside-down shipwreck in the specified world seed and coordinates. What the problem with this one is that it is generated abnormally on an incorrect y-axis making it float in the air. It is also very odd to see one in the center of the Frozen Ocean iceberg without any gap, leaving a question to the players how it went inside the surrounding Iceberg without any possible entrances.

 Updated: I added a new screenshot of a shipwreck merged inside the beach biome, a very bizarre occurrence.