Strange shipwreck generation after converting world from 1.14 to 1.18 snapshot

So I was messing around with the new terrain blending features of the 1.18 snapshots and I found something strange.

I flew around and found a shipwreck in a mountain. I used the /locatebiome command to see if there was perhaps a single block of ocean nearby, but all ocean types were 700-1000 blocks away.

I have no idea why this shipwreck generated here, but it looks pretty cool. Would be awesome to make a base out of!

 

I hope my information helps