/spreadplayers command does not allow for negative "under" values

The world height has been decreased from 0 to -64, yet the command height limit has not been updated to reflect this. The spreadplayers command does not allow for numbers under values less than 0 still, stating that the number must be above 0 even though the world generates lower now.

To reproduce

 /spreadplayers ~ ~ 0 1 under -1 false @s