A homogeneous A2-tilde building with a non-discrete automorphism group is Bruhat-Tits

Let Delta be a locally finite thick building of type A2-tilde. We show that, if the type-preserving automorphism group Aut(Delta)+ of Delta is transitive on panels of each type, then either Delta is Bruhat-Tits or Aut(Delta) is discrete. For A2-tilde buildings which are not panel-transitive but only vertex-transitive, we give additional conditions under which the same conclusion holds. We also find a local condition under which an A2-tilde building is ensured to be exotic (i.e. not Bruhat-Tits). It can be used to show that the number of exotic A2-tilde buildings with thickness q+1 and admitting a panel-regular lattice grows super-exponentially with q (ranging over prime powers). All those exotic A2-tilde buildings have a discrete automorphism group.