Creating a world with the seed -630666582824199719 results in huge world generation gliches.
First, I created a new world and only changed the default gamemode to Creative and the world name. I didn't even touch the advanced settings! Then I noticed there are world generation gliches everywhere. A few examples:
Then I made another world, this time I manually changed the seed to the same one as the world before (-630666582824199719). The terrain was completely different (I also checked the spawn coordinates, they were the same), but there were some gliches as well, for example:
I also generated some other worlds with random seeds, and they all generated normally so it must be an issue with the seed.