Math error (random generation of zero) causing map gen to fail

Let me preface this by saying that I like this quirk, and don't want it to be removed either.

But that said, quirks like this are hard to keep - they're (by definition) generated by situations that the developers didn't expect would happen. And as such, it's possible for them to accidently be removed or changed without realizing it. (This specific case, that's unlikely, but for similar properties, it's another story). And not only that, you do have to worry about places where it causes errors - for instance, it is feasible for a similar issue with another type of structure to cause the world to not stop generating, as one structure generates, and then another, repeatedly. (That, also, is unlikely, but possible).

So knowing why it happens and how it works is very important. That doesn't mean it needs to be fixed, but it still needs to be investigated and checked for related issues.

Confirmed for 18w09a

You can get similar seeds that produce the same effect by adding or subtracting a factor of 281474976710656 to the number (as in calculation, not in concatenation).
Sample seeds that produce the same effect:
-174436595872572
388513357548740

-117163709839622
445786243581690

There are in total 131,072 seeds (65,536 for each axis) that are affected.

Affects 18w16a. Not that I want this fixed.

There is actually 274,877,906,944 broken seeds.
https://youtu.be/l8_1O4dO3Bg