All Mesa (Bryce) Biomes from 1.11 up to 18w10d (didn't check earlier versions) cut off at chunk borders and are floating above sea level. This bug has been reported before, seemingly fixed but still exists.

Example Seed: 3083649240941742694

• Example Location 1: Directly at Spawn (close to -400 - 100)
• Example Location 2: -8430 9740

Notice how the Bryce doesn't generate properly in the chunks it's supposed to be in (Huge Biome Borders) and that the whole thing is flying when above water.

Old Issues:
https://bugs.mojang.com/browse/MC-67468?jql=text%20~%20"Bryce"
https://bugs.mojang.com/browse/MC-86405?jql=text%20~%20"Bryce"

Notice how the chunk borders were properly generates before.