2 stables at once? I find that hard to believe.

This is a bug in the generator: the limit on the maximum number in a zone is not correctly taken into account when forming a group of objects (in the sense of a set of objects standing next to each other, which would be guarded by a single common guard if they had sufficient value). That is, if the generator has already placed a stable in the zone, it will not place another one, but if it has not yet placed one, it may place 2 at once (or even more).