The seed -6892427001463366129 might reveal some flaws in terrain generation. There are multiple blocky shapes towards the ground. Above that, far into the sky is another blocky floating island. Even further is another island the generates above the first. The entire area surrounding this possible error is more unorthodox and blocky islands, some floating, some not. Whilst this is somewhat cool, it reminds me of old chunk errors where the player would see sharp right angles and floating masses. 

Although the screenshots are taken on a modded client, I confirmed that this issue persists in a fully unmodified instance. 

Quick remark: this is not a world upgrade from a previous version. This is a fresh world generated in 1.18 pre-release 5