[phenixbb] dihedral restraints problem with alternate conformations

I am having an issue refining 2 superimposed MES molecules A and B (morpholino ethane sulfonic acid, buffer seen in the density). phenix.refine works fine up to the end where it crashes because of the following error: Duplicate dihedral restraints: tor id: var_10 residue: MES, conformer "A" atoms: "HETATM 3993 O1 AMES T 1 .*. O " "HETATM 3994 C2 AMES T 1 .*. C " "HETATM 3995 C3 AMES T 1 .*. C " "HETATM 3996 N4 AMES T 1 .*. N+1" I can't see where is the conflict since all atoms have distinct labels and I provided the CIF file generated with phenix.elbow. What should I change to circumvent this problem? Thanks Ben