Here is the "worldgen_settings.json" file I imported and the crash report.
MC-207305
Minecraft crashes when trying to generate a custom world with "min_y" set to -512 and "height" set to 512
Resolved
Cannot Reproduce
2
It seems like it works if "min_y" is set to 0. Is this intentional? Isn't the point of "min_y" to allow worlds to reach negative Y levels?