Hyperpolarity of polar foliations of codimension two

We consider polar foliations of codimension two on compact simply connected irreducible symmetric spaces. In rank at least two, we prove that these foliations are hyperpolar, settling the remaining case of the hyperpolarity problem discussed by Lytchak. We show that, for irreducible spherical Coxeter quotients, the horizontal universal cover fails to be a spherical building precisely on the Cayley plane, where every such foliation is congruent to one of the two known homogeneous models.