Nonunique down-set extremizers for Harper theorem

Equality in Harper theorem need not make a down-set a cube-automorphic image of a simplicial initial segment. In $Q_4$, take all sets of size at most one and the four two-element sets forming a four-cycle. This family has size nine and closed graph neighbourhood size fifteen, just like the size-nine simplicial order on the discrete cube initial segment. The induced degree of a vertex distributions differ, so they cannot be related by a graph automorphism.